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Vol. 80
Friday,
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September 4, 2015
Part III
Department of Commerce
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National Oceanic and Atmospheric Administration
Takes of Marine Mammals Incidental to Specified Activities; U.S. Navy
Civilian Port Defense Activities at the Ports of Los Angeles/Long Beach,
California; Notice
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Federal Register / Vol. 80, No. 172 / Friday, September 4, 2015 / Notices
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric
Administration
RIN 0648–XE131
Takes of Marine Mammals Incidental to
Specified Activities; U.S. Navy Civilian
Port Defense Activities at the Ports of
Los Angeles/Long Beach, California
National Marine Fisheries
Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA),
Commerce.
ACTION: Notice; proposed incidental
harassment authorization; request for
comments.
AGENCY:
NMFS has received a request
from the U.S. Navy (Navy) for an
Incidental Harassment Authorization
(IHA) to take marine mammals, by
harassment, incidental to Civilian Port
defense activities within and near the
Ports of Los Angeles and Long Beach
from October through November 2015.
Pursuant to the Marine Mammal
Protection Act (MMPA), NMFS is
requesting comments on its proposal to
issue an IHA to the Navy to incidentally
take, by Level B harassment only,
marine mammals during the specified
activity.
SUMMARY:
Comments and information must
be received no later than October 5,
2015.
DATES:
Comments on the Navy’s
IHA application (the application)
should be addressed to Jolie Harrison,
Chief, Permits and Conservation
Division, Office of Protected Resources,
National Marine Fisheries Service, 1315
East-West Highway, Silver Spring, MD
20910. The mailbox address for
providing email comments is
itp.fiorentino@noaa.gov. Comments sent
via email, including all attachments,
must not exceed a 25-megabyte file size.
NMFS is not responsible for comments
sent to addresses other than those
provided here.
Instructions: All comments received
are a part of the public record and will
generally be posted to http://
www.nmfs.noaa.gov/pr/permits/
incidental/ without change. All Personal
Identifying Information (for example,
name, address, etc.) voluntarily
submitted by the commenter may be
publicly accessible. Do not submit
Confidential Business Information or
otherwise sensitive or protected
information.
An electronic copy of the application
may be obtained by writing to the
address specified above, telephoning the
contact listed below (see FOR FURTHER
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ADDRESSES:
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INFORMATION CONTACT), or visiting the
Internet at: http://www.nmfs.noaa.gov/
pr/permits/incidental/. Documents cited
in this notice may also be viewed, by
appointment, during regular business
hours, at the aforementioned address.
The Navy is also preparing an
Environmental Assessment (EA) in
accordance with the National
Environmental Policy Act (NEPA), to
evaluate all components of the proposed
Civilian Port Defense training activities.
NMFS intends to adopt the Navy’s EA,
if adequate and appropriate. Currently,
we believe that the adoption of the
Navy’s EA will allow NMFS to meet its
responsibilities under NEPA for the
issuance of an IHA to the Navy for
Civilian Port Defense activities at the
Ports of Los Angeles and Long Beach
Harbor. If necessary, however, NMFS
will supplement the existing analysis to
ensure that we comply with NEPA prior
to the issuance of the final IHA.
FOR FURTHER INFORMATION CONTACT: John
Fiorentino, Office of Protected
Resources, NMFS, (301) 427–8477.
SUPPLEMENTARY INFORMATION:
amended the definition of ‘‘harassment’’
as it applies to a ‘‘military readiness
activity’’ to read as follows (Section
3(18)(B) of the MMPA): (i) Any act that
injures or has the significant potential to
injure a marine mammal or marine
mammal stock in the wild [Level A
Harassment]; or (ii) Any act that
disturbs or is likely to disturb a marine
mammal or marine mammal stock in the
wild by causing disruption of natural
behavioral patterns, to a point where
such behavioral patterns are abandoned
or significantly altered [Level B
Harassment].
Except with respect to certain
activities not pertinent here, the MMPA
defines ‘‘harassment’’ as: Any act of
pursuit, torment, or annoyance which (i)
has the potential to injure a marine
mammal or marine mammal stock in the
wild [Level A harassment]; or (ii) has
the potential to disturb a marine
mammal or marine mammal stock in the
wild by causing disruption of behavioral
patterns, including, but not limited to,
migration, breathing, nursing, breeding,
feeding, or sheltering [Level B
harassment].
Background
Summary of Request
On April 16, 2015, NMFS received an
application from the Navy requesting an
IHA for the taking of marine mammals
incidental to Civilian Port Defense
activities at the Ports of Los Angeles and
Long Beach, California from October
through November, 2015.
The Study Area includes the waters
within and near the Ports of Los Angeles
and Long Beach, California. Since the
Ports of Los Angeles and Long Beach are
adjacent and are both encompassed
within the larger proposed action area
(Study Area) they will be described
collectively as Los Angeles/Long Beach
(see Figure 2–1 of the application for a
map of the Study Area). These activities
are classified as military readiness
activities. Marine mammals present in
the Study Area may be exposed to
sound from active acoustic sources
(sonar). The Navy is requesting
authorization to take 7 marine mammal
species by Level B harassment
(behavioral). No injurious takes (Level A
harassment) of marine mammals are
predicted and, therefore, none are being
authorized.
Sections 101(a)(5)(A) and (D) of the
MMPA (16 U.S.C. 1361 et seq.) direct
the Secretary of Commerce to allow,
upon request, the incidental, but not
intentional, taking of small numbers of
marine mammals by U.S. citizens who
engage in a specified activity (other than
commercial fishing) within a specified
geographical region if certain findings
are made and either regulations are
issued or, if the taking is limited to
harassment, a notice of a proposed
authorization is provided to the public
for review.
An authorization for incidental
takings shall be granted if NMFS finds
that the taking will have a negligible
impact on the species or stock(s), will
not have an unmitigable adverse impact
on the availability of the species or
stock(s) for subsistence uses (where
relevant), and if the permissible
methods of taking and requirements
pertaining to the mitigation, monitoring
and reporting of such takings are set
forth. NMFS has defined ‘‘negligible
impact’’ in 50 CFR 216.103 as ‘‘an
impact resulting from the specified
activity that cannot be reasonably
expected to, and is not reasonably likely
to, adversely affect the species or stock
through effects on annual rates of
recruitment or survival.’’
The National Defense Authorization
Act of 2004 (NDAA) (Pub. L. 108–136)
removed the ‘‘small numbers’’ and
‘‘specified geographical region’’
limitations indicated above and
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Description of the Specified Activity
Civilian Port Defense activities are
naval mine warfare exercises conducted
in support of maritime homeland
defense, per the Maritime Operational
Threat Response Plan. These activities
are conducted in conjunction with other
federal agencies, principally the
Department of Homeland Security. The
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three pillars of Mine Warfare include
airborne (helicopter), surface (ship and
unmanned vehicles), and undersea
(divers, marine mammal systems, and
unmanned vehicles), all of which are
used in order to ensure that strategic
U.S. ports are cleared of mine threats.
Civilian Port Defense events are
conducted in ports or major
surrounding waterways, within the
shipping lanes, and seaward to the 300
feet (ft, 91 meters [m]) depth contour.
The events employ the use of various
mine detection sensors, some of which
utilize active acoustics for detection of
mines and mine-like objects in and
around various ports. Assets used
during Civilian Port Defense training
include up to four unmanned
underwater vehicles, marine mammal
systems, up to two helicopters operating
(two to four hours) at altitudes as low
as 75 to 100 ft (23 to 31 m), explosive
ordnance disposal platoons, a Littoral
Combat Ship or Landing Dock Platform
and AVENGER class ships. The
AVENGER is a surface mine
countermeasure vessel specifically
outfitted for mine countermeasure
capability. The proposed Civilian Port
Defense activities for Los Angeles/Long
Beach include the use of up to 20
bottom placed non explosive mine
training shapes. Mine shapes may be
retrieved by Navy divers, typically
explosive ordnance disposal personnel,
and may be brought to beach side
locations to ensure that the
neutralization measures are effective
and the shapes are secured. The final
step to the beach side activity is the
intelligence gathering and identifying
how the mine works, disassembling it or
neutralizing it. The entire training event
takes place over multiple weeks
utilizing a variety of assets and
scenarios. The following descriptions
detail the possible range of activities
which could take place during a
Civilian Port Defense training event.
This is all inclusive and many of these
activities are not included within the
analysis of this specific event. Mine
detection including towed or hull
mounted sources would be the only
portion of this event which we are
proposing authorization.
Mine Detection Systems
Mine detection systems are used to
locate, classify, and map suspected
mines (Figure 1–1 of the application).
Once located, the mines can either be
neutralized or avoided. These systems
are specialized to either locate mines on
the surface, in the water column, or on
the sea floor.
• Towed or Hull-Mounted Mine
Detection Systems. These detection
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systems use acoustic and laser or video
sensors to locate and classify suspect
mines. Helicopters, ships, and
unmanned vehicles are used with towed
systems, which can rapidly assess large
areas.
• Unmanned/Remotely Operated
Vehicles. These vehicles use acoustic
and video or lasers systems to locate
and classify mines. Unmanned/remotely
operated vehicles provide mine warfare
capabilities in nearshore littoral areas,
surf zones, ports, and channels.
• Airborne Laser Mine Detection
Systems. Airborne laser detection
systems work in concert with
neutralization systems. The detection
system initially locates mines and a
neutralization system is then used to
relocate and neutralize the mine.
• Marine Mammal Systems. Navy
personnel and Navy marine mammals
work together to detect specified
underwater objects. The Navy deploys
trained bottlenose dolphins and
California sea lions as part of the marine
mammal mine-hunting and objectrecovery system.
Sonar systems to be used during
Civilian Port Defense Mine Detection
training would include AN/SQQ–32,
AN/SLQ–48, AN/AQS–24, and
handheld sonars (e.g., AN/PQS–2A). Of
these sonar sources, only the AN/SQQ–
32 would require quantitative acoustic
effects analysis, given its source
parameters. The AN/SQQ–32 is a high
frequency (between 10 and 200
kilohertz [kHz]) sonar system; the
specific source parameters of the AN/
SQQ–32 are classified. The AN/AQS–
24, AN/SLQ–48 and handheld sonars
are considered de minimis sources,
which are defined as sources with low
source levels, narrow beams, downward
directed transmission, short pulse
lengths, frequencies above known
hearing ranges, or some combination of
these factors (Department of the Navy
2013). De minimis sources have been
determined to not have potential impact
to marine mammals.
Mine Neutralization
Mine neutralization systems disrupt,
disable, or detonate mines to clear ports
and shipping lanes. Mine neutralization
systems can clear individual mines or a
large number of mines quickly. Two
types of mine neutralization could be
conducted, mechanical minesweeping
and influence system minesweeping.
Mechanical minesweeping consists of
cutting the tether of mines moored in
the water column or other means of
physically releasing the mine. Moored
mines cut loose by mechanical
sweeping must then be neutralized or
rendered safe for subsequent analysis.
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Influence minesweeping consists of
simulating the magnetic, electric,
acoustic, seismic, or pressure signature
of a ship so that the mine detonates (no
detonations would occur as part of the
proposed training activities). Mine
neutralization is included here to
present the full spectrum of Civilian
Port Defense Mine Warfare activities.
The mine neutralization component of
the proposed Civilian Port Defense
training activities will not result in the
incidental taking of marine mammals.
Dates, Duration, and Geographic
Region
Civilian Port Defense training
activities are scheduled every year,
typically alternating between the east
and west coasts of the United States.
Civilian Port Defense activities in 2015
are proposed to occur on the U.S. west
coast near Los Angeles/Long Beach,
California. Civilian Port Defense events
are typically conducted in areas of ports
or major surrounding waterways and
within the shipping lanes and seaward
to the 300 ft (91 m) depth contour.
Civilian Port Defense activities would
occur at the Ports of Los Angeles/Long
Beach during October through
November 2015 (Figure 2–1 of the
application). The training exercise
would occur for a period of two weeks
in which active sonar would be utilized
for two separate periods of four day long
events. The AN/SQQ–32 sonar could be
active for up to 24 hours a day during
these training events; however, the use
of the AN/SQQ–32 would not be
continuously active during the four day
long period. Additional activities would
occur during this time and are analyzed
within the Navy’s Environmental
Assessment for Civilian Port Defense
training activities. The Navy has
determined there is potential for take as
defined under MMPA for military
readiness activities. Specifically take
has potential to occur from utilization of
active sonar sources. This stressor is the
only aspect of the proposed training
activities for which this IHA is being
requested.
The Ports of Los Angeles and Long
Beach combined represent the busiest
port along the U.S. West Coast and
second busiest in the United States. In
2012 and 2013, approximately 4,550
and 4,500 vessel calls, respectively, for
ships over 10,000 deadweight tons
arrived at the Ports of Los Angeles and
Long Beach (Louttit and Chavez 2014;
U.S. Department of Transportation).
This level of shipping would mean
approximately 9,000 large ship transits
to and from these ports and through the
Study Area. By comparison, the next
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nearest large regional port, Port of San
Diego, only had 318 vessel calls in 2012.
Description of Marine Mammals in the
Area of the Specified Activity
Nineteen marine mammal species are
known to occur in the study area,
including five mysticetes (baleen
whales), nine odontocetes (dolphins and
toothed whales), and five pinnipeds
(seals and sea lions). Among these
species are 31 stocks managed by
NMFS. All species were quantitatively
analyzed in the Navy Acoustic Effects
Model (NAEMO; see Chapter 6.4 of the
application for additional information
on the modeling process). After
completing the modeling simulations,
seven species (each with a single stock)
are estimated to potentially be taken by
harassment as defined by the MMPA, as
it applies to military readiness, during
the proposed Civilian Port Defense
activities due to use of active sonar
sources. Based on a variety of factors,
including source characterization,
species presence, species hearing range,
duration of exposure, and impact
thresholds for species that may be
present, the remainder of the species
were not quantitatively predicted to be
exposed to or affected by active acoustic
transmissions related to the proposed
activities that would result in
harassment under the MMPA and,
therefore, are not discussed further.
Other potential stressors related to the
proposed Civilian Port Defense
activities (e.g., vessel movement/noise,
in water device use) would not result in
disruption or alteration of breeding,
feeding, or nursing patterns that that
would rise to a level of significance
under the MMPA. The seven species
with the potential to be taken by
harassment during the proposed
training activities are presented in Table
1 and relevant information on their
status, behavior, life history,
distribution, abundance, and hearing
and vocalization is presented in Chapter
4 of the application. Further information
on the general biology and ecology of
marine mammals is included in the
Navy’s EA. In addition, NMFS publishes
annual SARs for marine mammals,
including stocks that occur within the
Study Area (http://www.nmfs.noaa.gov/
pr/species/mammals; Carretta et al.,
2014; Allen and Angliss, 2014).
TABLE 1—MARINE MAMMAL SPECIES WITH ESTIMATED EXPOSURES ABOVE HARASSMENT THRESHOLDS IN THE STUDY
AREA
Species
Stock abundance 1
(coefficient of
variance)
Stock
Occurrence, seasonality, and duration in study area
Odontocetes
Long-beaked common dolphin
(Delphinus capensis).
California ...................................
107,016 (0.42)
Short-beaked common dolphin
(Delphinus delphis).
California, Oregon, Washington
411,211 (0.21)
Risso’s dolphin (Grampus
griseus).
California, Oregon, Washington
6,272 (0.30)
Pacific white-sided dolphin
California, Oregon, Washington
(Lagenorhynchus obilquidens).
26,930 (0.28)
Bottlenose dolphin coastal
(Tursiops truncatus).
Coastal California ......................
323 (0.13)
Common inshore of 820 ft (250 m) isobath. Species
may be more abundant in study area from May to
October.
Primary occurrence between the coast and 300 nautical miles (nm) from shore. Prefers water depths
between 650 and 6,500 ft (200 and 2,000 m).
Frequently observed in waters surrounding San
Clemente Island, California. Occurs on the shelf in
the Southern California Bight. Highest abundance
is in the cold season.
Occurs primarily in shelf and slope waters of California; spends more time in California waters in
colder water months.
Small, limited population; found within 1,640 ft (500
m) of the shoreline 99 percent of the time and
within 820 ft (250 m) 90 percent of the time.
Pinnipeds
Harbor seal (Phoca vitulina) ......
California ...................................
California sea lion (Zalophus
californianus).
U.S. ...........................................
2 30,196
(0.157)
296,750
Found in moderate numbers. Concentrate around
haul-outs in the Channel Islands.
Most common pinniped. Primarily congregate around
the Channel Islands. Peak abundance is from May
to August.
1 From:
Carretta et al. (2014). U.S. Pacific Marine Mammal Stock Assessments, 2013.
draft U.S. Pacific Marine Mammal Stock Assessments, 2014 is proposing a small revision to the California stock of harbor seals from
30,196 to 30,968. No other proposed revisions are anticipated for these species.
2 NMFS’
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Marine Mammal Hearing and
Vocalizations
Cetaceans have an auditory anatomy
that follows the basic mammalian
pattern, with some changes to adapt to
the demands of hearing underwater. The
typical mammalian ear is divided into
an outer ear, middle ear, and inner ear.
The outer ear is separated from the
inner ear by a tympanic membrane, or
eardrum. In terrestrial mammals, the
outer ear, eardrum, and middle ear
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transmit airborne sound to the inner ear,
where the sound waves are propagated
through the cochlear fluid. Since the
impedance of water is close to that of
the tissues of a cetacean, the outer ear
is not required to transduce sound
energy as it does when sound waves
travel from air to fluid (inner ear).
Sound waves traveling through the
inner ear cause the basilar membrane to
vibrate. Specialized cells, called hair
cells, respond to the vibration and
produce nerve pulses that are
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transmitted to the central nervous
system. Acoustic energy causes the
basilar membrane in the cochlea to
vibrate. Sensory cells at different
positions along the basilar membrane
are excited by different frequencies of
sound (Pickles, 1998).
Marine mammal vocalizations often
extend both above and below the range
of human hearing; vocalizations with
frequencies lower than 20 Hz are
labeled as infrasonic and those higher
than 20 kHz as ultrasonic (National
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Research Council (NRC), 2003; Figure
4–1). Measured data on the hearing
abilities of cetaceans are sparse,
particularly for the larger cetaceans such
as the baleen whales. The auditory
thresholds of some of the smaller
odontocetes have been determined in
captivity. It is generally believed that
cetaceans should at least be sensitive to
the frequencies of their own
vocalizations. Comparisons of the
anatomy of cetacean inner ears and
models of the structural properties and
the response to vibrations of the ear’s
components in different species provide
an indication of likely sensitivity to
various sound frequencies. The ears of
small toothed whales are optimized for
receiving high-frequency sound, while
baleen whale inner ears are best in low
to infrasonic frequencies (Ketten, 1992;
1997; 1998).
Baleen whale vocalizations are
composed primarily of frequencies
below 1 kHz, and some contain
fundamental frequencies as low as 16
Hz (Watkins et al., 1987; Richardson et
al., 1995; Rivers, 1997; Moore et al.,
1998; Stafford et al., 1999; Wartzok and
Ketten, 1999) but can be as high as 24
kHz (humpback whale; Au et al., 2006).
Clark and Ellison (2004) suggested that
baleen whales use low-frequency
sounds not only for long-range
communication, but also as a simple
form of echo ranging, using echoes to
navigate and orient relative to physical
features of the ocean. Information on
auditory function in baleen whales is
extremely lacking. Sensitivity to lowfrequency sound by baleen whales has
been inferred from observed
vocalization frequencies, observed
reactions to playback of sounds, and
anatomical analyses of the auditory
system. Although there is apparently
much variation, the source levels of
most baleen whale vocalizations lie in
the range of 150–190 dB re 1
microPascal (mPa) at 1 m. Lowfrequency vocalizations made by baleen
whales and their corresponding
auditory anatomy suggest that they have
good low-frequency hearing (Ketten,
2000), although specific data on
sensitivity, frequency or intensity
discrimination, or localization abilities
are lacking. Marine mammals, like all
mammals, have typical U-shaped
audiograms that begin with relatively
low sensitivity (high threshold) at some
specified low frequency with increased
sensitivity (low threshold) to a species
specific optimum followed by a
generally steep rise at higher
frequencies (high threshold) (Fay, 1988).
The toothed whales produce a wide
variety of sounds, which include
species-specific broadband ‘‘clicks’’
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with peak energy between 10 and 200
kHz, individually variable ‘‘burst pulse’’
click trains, and constant frequency or
frequency-modulated (FM) whistles
ranging from 4 to 16 kHz (Wartzok and
Ketten, 1999). The general consensus is
that the tonal vocalizations (whistles)
produced by toothed whales play an
important role in maintaining contact
between dispersed individuals, while
broadband clicks are used during
echolocation (Wartzok and Ketten,
1999). Burst pulses have also been
strongly implicated in communication,
with some scientists suggesting that
they play an important role in agonistic
encounters (McCowan and Reiss, 1995),
while others have proposed that they
represent ‘‘emotive’’ signals in a broader
sense, possibly representing graded
communication signals (Herzing, 1996).
Sperm whales, however, are known to
produce only clicks, which are used for
both communication and echolocation
(Whitehead, 2003). Most of the energy of
toothed whale social vocalizations is
concentrated near 10 kHz, with source
levels for whistles as high as 100 to 180
dB re 1 mPa at 1 m (Richardson et al.,
1995). No odontocete has been shown
audiometrically to have acute hearing
(<80 dB re 1 mPa) below 500 Hz (DoN,
2001). Sperm whales produce clicks,
which may be used to echolocate
(Mullins et al., 1988), with a frequency
range from less than 100 Hz to 30 kHz
and source levels up to 230 dB re 1 mPa
1 m or greater (Mohl et al., 2000).
Brief Background on Sound
An understanding of the basic
properties of underwater sound is
necessary to comprehend many of the
concepts and analyses presented in this
document. A summary is included
below.
Sound is a wave of pressure variations
propagating through a medium (e.g.,
water). Pressure variations are created
by compressing and relaxing the
medium. Sound measurements can be
expressed in two forms: intensity and
pressure. Acoustic intensity is the
average rate of energy transmitted
through a unit area in a specified
direction and is expressed in watts per
square meter (W/m2). Acoustic intensity
is rarely measured directly, but rather
from ratios of pressures; the standard
reference pressure for underwater sound
is 1 mPa; for airborne sound, the
standard reference pressure is 20 mPa
(Richardson et al., 1995).
Acousticians have adopted a
logarithmic scale for sound intensities,
which is denoted in decibels (dB).
Decibel measurements represent the
ratio between a measured pressure value
and a reference pressure value (in this
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case 1 mPa or, for airborne sound, 20
mPa). The logarithmic nature of the scale
means that each 10-dB increase is a tenfold increase in acoustic power (and a
20-dB increase is then a 100-fold
increase in power; and a 30-dB increase
is a 1,000-fold increase in power). A tenfold increase in acoustic power does not
mean that the sound is perceived as
being ten times louder, however.
Humans perceive a 10-dB increase in
sound level as a doubling of loudness,
and a 10-dB decrease in sound level as
a halving of loudness. The term ‘‘sound
pressure level’’ implies a decibel
measure and a reference pressure that is
used as the denominator of the ratio.
Throughout this document, NMFS uses
1 mPa (denoted re: 1mPa) as a standard
reference pressure unless noted
otherwise.
It is important to note that decibel
values underwater and decibel values in
air are not the same (different reference
pressures and densities/sound speeds
between media) and should not be
directly compared. Because of the
different densities of air and water and
the different decibel standards (i.e.,
reference pressures) in air and water, a
sound with the same level in air and in
water would be approximately 62 dB
lower in air. Thus, a sound that
measures 160 dB (re 1 mPa) underwater
would have the same approximate
effective level as a sound that is 98 dB
(re 20 mPa) in air.
Sound frequency is measured in
cycles per second, or Hertz (abbreviated
Hz), and is analogous to musical pitch;
high-pitched sounds contain high
frequencies and low-pitched sounds
contain low frequencies. Natural sounds
in the ocean span a huge range of
frequencies: from earthquake noise at 5
Hz to harbor porpoise clicks at 150,000
Hz (150 kHz). These sounds are so low
or so high in pitch that humans cannot
even hear them; acousticians call these
infrasonic (typically below 20 Hz) and
ultrasonic (typically above 20,000 Hz)
sounds, respectively. A single sound
may be made up of many different
frequencies together. Sounds made up
of only a small range of frequencies are
called ‘‘narrowband’’, and sounds with
a broad range of frequencies are called
‘‘broadband’’; explosives are an example
of a broadband sound source and active
tactical sonars are an example of a
narrowband sound source.
When considering the influence of
various kinds of sound on the marine
environment, it is necessary to
understand that different kinds of
marine life are sensitive to different
frequencies of sound. Current data
indicate that not all marine mammal
species have equal hearing capabilities
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(Richardson et al., 1995; Southall et al.,
1997; Wartzok and Ketten, 1999; Au and
Hastings, 2008).
Southall et al. (2007) designated
‘‘functional hearing groups’’ for marine
mammals based on available behavioral
data; audiograms derived from auditory
evoked potentials; anatomical modeling;
and other data. Southall et al. (2007)
also estimated the lower and upper
frequencies of functional hearing for
each group. However, animals are less
sensitive to sounds at the outer edges of
their functional hearing range and are
more sensitive to a range of frequencies
within the middle of their functional
hearing range. Note that direct
measurements of hearing sensitivity do
not exist for all species of marine
mammals, including low-frequency
cetaceans. The functional hearing
groups and the associated frequencies
developed by Southall et al. (2007) were
revised by Finneran and Jenkins (2012)
and have been further modified by
NOAA. Table 2 provides a summary of
sound production and general hearing
capabilities for marine mammal species
(note that values in this table are not
meant to reflect absolute possible
maximum ranges, rather they represent
the best known ranges of each
functional hearing group). For purposes
of the analysis in this document, marine
mammals are arranged into the
following functional hearing groups
based on their generalized hearing
sensitivities: High-frequency cetaceans,
mid-frequency cetaceans, low-frequency
cetaceans (mysticetes), phocids (true
seals), otariids (sea lion and fur seals),
and mustelids (sea otters). A detailed
discussion of the functional hearing
groups can be found in Southall et al.
(2007) and Finneran and Jenkins (2012).
TABLE 2—MARINE MAMMAL FUNCTIONAL HEARING GROUPS
Functional hearing group
Functional hearing range *
Low-frequency (LF) cetaceans (baleen whales) ...................................................................................
Mid-frequency (MF) cetaceans (dolphins, toothed whales, beaked whales, bottlenose whales) ........
High-frequency (HF) cetaceans (true porpoises, Kogia, river dolphins, cephalorhynchid,
Lagenorhynchus cruciger & L. australis).
Phocid pinnipeds (underwater) (true seals) ..........................................................................................
Otariid pinnipeds (underwater) (sea lions and fur seals) ......................................................................
7 Hz to 25 kHz.
150 Hz to 160 kHz.
200 Hz to 180 kHz.
75 Hz to 100 kHz.
100 Hz to 48 kHz.
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Adapted and derived from Southall et al. (2007).
* Represents frequency band of hearing for entire group as a composite (i.e., all species within the group), where individual species’ hearing
ranges are typically not as broad. Functional hearing is defined as the range of frequencies a group hears without incorporating non-acoustic
mechanisms (Wartzok and Ketten, 1999). This is ∼ 60 to ∼ 70 dB above best hearing sensitivity (Southall et al., 2007) for all functional hearing
groups except LF cetaceans, where no direct measurements on hearing are available. For LF cetaceans, the lower range is based on recommendations from Southall et al., 2007 and the upper range is based on information on inner ear anatomy and vocalizations.
When sound travels (propagates) from
its source, its loudness decreases as the
distance traveled by the sound
increases. Thus, the loudness of a sound
at its source is higher than the loudness
of that same sound a kilometer away.
Acousticians often refer to the loudness
of a sound at its source (typically
referenced to one meter from the source)
as the source level and the loudness of
sound elsewhere as the received level
(i.e., typically the receiver). For
example, a humpback whale 3 km from
a device that has a source level of 230
dB may only be exposed to sound that
is 160 dB loud, depending on how the
sound travels through water (e.g.,
spherical spreading [3 dB reduction
with doubling of distance] was used in
this example). As a result, it is
important to understand the difference
between source levels and received
levels when discussing the loudness of
sound in the ocean or its impacts on the
marine environment.
As sound travels from a source, its
propagation in water is influenced by
various physical characteristics,
including water temperature, depth,
salinity, and surface and bottom
properties that cause refraction,
reflection, absorption, and scattering of
sound waves. Oceans are not
homogeneous and the contribution of
each of these individual factors is
extremely complex and interrelated.
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The physical characteristics that
determine the sound’s speed through
the water will change with depth,
season, geographic location, and with
time of day (as a result, in actual active
sonar operations, crews will measure
oceanic conditions, such as sea water
temperature and depth, to calibrate
models that determine the path the
sonar signal will take as it travels
through the ocean and how strong the
sound signal will be at a given range
along a particular transmission path). As
sound travels through the ocean, the
intensity associated with the wavefront
diminishes, or attenuates. This decrease
in intensity is referred to as propagation
loss, also commonly called transmission
loss.
Metrics Used in This Document
This section includes a brief
explanation of the two sound
measurements (sound pressure level
(SPL) and sound exposure level (SEL))
frequently used to describe sound levels
in the discussions of acoustic effects in
this document.
Sound pressure level (SPL)—Sound
pressure is the sound force per unit
area, and is usually measured in
micropascals (mPa), where 1 Pa is the
pressure resulting from a force of one
newton exerted over an area of one
square meter. SPL is expressed as the
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ratio of a measured sound pressure and
a reference level.
SPL (in dB) = 20 log (pressure/reference
pressure)
The commonly used reference
pressure level in underwater acoustics
is 1 mPa, and the units for SPLs are dB
re: 1 mPa. SPL is an instantaneous
pressure measurement and can be
expressed as the peak, the peak-peak, or
the root mean square (rms). Root mean
square pressure, which is the square
root of the arithmetic average of the
squared instantaneous pressure values,
is typically used in discussions of the
effects of sounds on vertebrates and all
references to SPL in this document refer
to the root mean square. SPL does not
take the duration of exposure into
account. SPL is the applicable metric
used in the risk continuum, which is
used to estimate behavioral harassment
takes (see Level B Harassment Risk
Function (Behavioral Harassment)
Section).
Sound exposure level (SEL)—SEL is
an energy metric that integrates the
squared instantaneous sound pressure
over a stated time interval. The units for
SEL are dB re: 1 mPa2-s. Below is a
simplified formula for SEL.
SEL = SPL + 10 log (duration in
seconds)
As applied to active sonar, the SEL
includes both the SPL of a sonar ping
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and the total duration. Longer duration
pings and/or pings with higher SPLs
will have a higher SEL. If an animal is
exposed to multiple pings, the SEL in
each individual ping is summed to
calculate the cumulative SEL. The
cumulative SEL depends on the SPL,
duration, and number of pings received.
The thresholds that NMFS uses to
indicate at what received level the onset
of temporary threshold shift (TTS) and
permanent threshold shift (PTS) in
hearing are likely to occur are expressed
as cumulative SEL.
Potential Effects of the Specified
Activity on Marine Mammals
The Navy has requested authorization
for the take of marine mammals that
may occur incidental to Civilian Port
Defense training activities in the Study
Area. The Navy has analyzed potential
impacts to marine mammals from nonimpulsive sound sources.
Other potential impacts to marine
mammals from training activities in the
Study Area were analyzed in the Navy’s
EA, and determined to be unlikely to
result in marine mammal harassment.
Therefore, the Navy has not requested
authorization for take of marine
mammals that might occur incidental to
other components of its proposed
activities. In this document, NMFS
analyzes the potential effects on marine
mammals from exposure to nonimpulsive sound sources (active sonar).
For the purpose of MMPA
authorizations, NMFS’ effects
assessments serve four primary
purposes: (1) To prescribe the
permissible methods of taking (i.e.,
Level B harassment (behavioral
harassment), Level A harassment
(injury), or mortality, including an
identification of the number and types
of take that could occur by harassment
or mortality) and to prescribe other
means of effecting the least practicable
adverse impact on such species or stock
and its habitat (i.e., mitigation); (2) to
determine whether the specified activity
would have a negligible impact on the
affected species or stocks of marine
mammals (based on the likelihood that
the activity would adversely affect the
species or stock through effects on
annual rates of recruitment or survival);
(3) to determine whether the specified
activity would have an unmitigable
adverse impact on the availability of the
species or stock(s) for subsistence uses;
and (4) to prescribe requirements
pertaining to monitoring and reporting.
More specifically, for activities
involving non-impulsive sources (active
sonar), NMFS’ analysis will identify the
probability of lethal responses, physical
trauma, sensory impairment (permanent
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and temporary threshold shifts and
acoustic masking), physiological
responses (particular stress responses),
behavioral disturbance (that rises to the
level of harassment), and social
responses (effects to social
relationships) that would be classified
as a take and whether such take would
have a negligible impact on such species
or stocks. This section focuses
qualitatively on the different ways that
non-impulsive sources may affect
marine mammals (some of which NMFS
would not classify as harassment).
Then, in the Estimated Take of Marine
Mammals section, the potential effects
to marine mammals from non-impulsive
sources will be related to the MMPA
definitions of Level B harassment, and
we will attempt to quantify those
effects.
Non-Impulsive Sources
Direct Physiological Effects
Based on the literature, there are two
basic ways that non-impulsive sources
might directly result in physical trauma
or damage: Noise-induced loss of
hearing sensitivity (more commonlycalled ‘‘threshold shift’’) and
acoustically mediated bubble growth.
Threshold Shift (noise-induced loss of
hearing)—When animals exhibit
reduced hearing sensitivity (i.e., sounds
must be louder for an animal to detect
them) following exposure to an intense
sound or sound for long duration, it is
referred to as a noise-induced threshold
shift (TS). An animal can experience
temporary threshold shift (TTS) or
permanent threshold shift (PTS). TTS
can last from minutes or hours to days
(i.e., there is complete recovery), can
occur in specific frequency ranges (i.e.,
an animal might only have a temporary
loss of hearing sensitivity between the
frequencies of 1 and 10 kHz), and can
be of varying amounts (for example, an
animal’s hearing sensitivity might be
reduced initially by only 6 dB or
reduced by 30 dB). PTS is permanent,
but some recovery is possible. PTS can
also occur in a specific frequency range
and amount as mentioned above for
TTS.
The following physiological
mechanisms are thought to play a role
in inducing auditory TS: Effects to
sensory hair cells in the inner ear that
reduce their sensitivity, modification of
the chemical environment within the
sensory cells, residual muscular activity
in the middle ear, displacement of
certain inner ear membranes, increased
blood flow, and post-stimulatory
reduction in both efferent and sensory
neural output (Southall et al., 2007).
The amplitude, duration, frequency,
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temporal pattern, and energy
distribution of sound exposure all can
affect the amount of associated TS and
the frequency range in which it occurs.
As amplitude and duration of sound
exposure increase, so, generally, does
the amount of TS, along with the
recovery time. For intermittent sounds,
less TS could occur than compared to a
continuous exposure with the same
energy (some recovery could occur
between intermittent exposures
depending on the duty cycle between
sounds) (Kryter et al., 1966; Ward,
1997). For example, one short but loud
(higher SPL) sound exposure may
induce the same impairment as one
longer but softer sound, which in turn
may cause more impairment than a
series of several intermittent softer
sounds with the same total energy
(Ward, 1997). Additionally, though TTS
is temporary, prolonged exposure to
sounds strong enough to elicit TTS, or
shorter-term exposure to sound levels
well above the TTS threshold, can cause
PTS, at least in terrestrial mammals
(Kryter, 1985). Although in the case of
mid- and high-frequency active sonar
(MFAS/HFAS), animals are not
expected to be exposed to levels high
enough or durations long enough to
result in PTS.
PTS is considered auditory injury
(Southall et al., 2007). Irreparable
damage to the inner or outer cochlear
hair cells may cause PTS; however,
other mechanisms are also involved,
such as exceeding the elastic limits of
certain tissues and membranes in the
middle and inner ears and resultant
changes in the chemical composition of
the inner ear fluids (Southall et al.,
2007).
Although the published body of
scientific literature contains numerous
theoretical studies and discussion
papers on hearing impairments that can
occur with exposure to a loud sound,
only a few studies provide empirical
information on the levels at which
noise-induced loss in hearing sensitivity
occurs in nonhuman animals. For
marine mammals, published data are
limited to the captive bottlenose
dolphin, beluga, harbor porpoise, and
Yangtze finless porpoise (Finneran et
al., 2000, 2002b, 2003, 2005a, 2007,
2010a, 2010b; Finneran and Schlundt,
2010; Lucke et al., 2009; Mooney et al.,
2009a, 2009b; Popov et al., 2011a,
2011b; Kastelein et al., 2012a; Schlundt
et al., 2000; Nachtigall et al., 2003,
2004). For pinnipeds in water, data are
limited to measurements of TTS in
harbor seals, an elephant seal, and
California sea lions (Kastak et al., 1999,
2005; Kastelein et al., 2012b).
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Marine mammal hearing plays a
critical role in communication with
conspecifics, and interpretation of
environmental cues for purposes such
as predator avoidance and prey capture.
Depending on the degree (elevation of
threshold in dB), duration (i.e., recovery
time), and frequency range of TTS, and
the context in which it is experienced,
TTS can have effects on marine
mammals ranging from discountable to
serious (similar to those discussed in
auditory masking, below). For example,
a marine mammal may be able to readily
compensate for a brief, relatively small
amount of TTS in a non-critical
frequency range that occurs during a
time where ambient noise is lower and
there are not as many competing sounds
present. Alternatively, a larger amount
and longer duration of TTS sustained
during time when communication is
critical for successful mother/calf
interactions could have more serious
impacts. Also, depending on the degree
and frequency range, the effects of PTS
on an animal could range in severity,
although it is considered generally more
serious because it is a permanent
condition. Of note, reduced hearing
sensitivity as a simple function of aging
has been observed in marine mammals,
as well as humans and other taxa
(Southall et al., 2007), so one can infer
that strategies exist for coping with this
condition to some degree, though likely
not without cost.
Acoustically Mediated Bubble
Growth—One theoretical cause of injury
to marine mammals is rectified
diffusion (Crum and Mao, 1996), the
process of increasing the size of a
bubble by exposing it to a sound field.
This process could be facilitated if the
environment in which the ensonified
bubbles exist is supersaturated with gas.
Repetitive diving by marine mammals
can cause the blood and some tissues to
accumulate gas to a greater degree than
is supported by the surrounding
environmental pressure (Ridgway and
Howard, 1979). The deeper and longer
dives of some marine mammals (for
example, beaked whales) are
theoretically predicted to induce greater
supersaturation (Houser et al., 2001b). If
rectified diffusion were possible in
marine mammals exposed to high-level
sound, conditions of tissue
supersaturation could theoretically
speed the rate and increase the size of
bubble growth. Subsequent effects due
to tissue trauma and emboli would
presumably mirror those observed in
humans suffering from decompression
sickness.
It is unlikely that the short duration
of sonar pings would be long enough to
drive bubble growth to any substantial
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size, if such a phenomenon occurs.
However, an alternative but related
hypothesis has also been suggested:
Stable bubbles could be destabilized by
high-level sound exposures such that
bubble growth then occurs through
static diffusion of gas out of the tissues.
In such a scenario the marine mammal
would need to be in a gassupersaturated state for a long enough
period of time for bubbles to become of
a problematic size. Recent research with
ex vivo supersaturated bovine tissues
suggested that, for a 37 kHz signal, a
sound exposure of approximately 215
dB referenced to (re) 1 mPa would be
required before microbubbles became
destabilized and grew (Crum et al.,
2005). Assuming spherical spreading
loss and a nominal sonar source level of
235 dB re 1 mPa at 1 m, a whale would
need to be within 10 m (33 ft.) of the
sonar dome to be exposed to such sound
levels. Furthermore, tissues in the study
were supersaturated by exposing them
to pressures of 400–700 kilopascals for
periods of hours and then releasing
them to ambient pressures. Assuming
the equilibration of gases with the
tissues occurred when the tissues were
exposed to the high pressures, levels of
supersaturation in the tissues could
have been as high as 400–700 percent.
These levels of tissue supersaturation
are substantially higher than model
predictions for marine mammals
(Houser et al., 2001; Saunders et al.,
2008). It is improbable that this
mechanism is responsible for stranding
events or traumas associated with
beaked whale strandings. Both the
degree of supersaturation and exposure
levels observed to cause microbubble
destabilization are unlikely to occur,
either alone or in concert.
Yet another hypothesis
(decompression sickness) has
speculated that rapid ascent to the
surface following exposure to a startling
sound might produce tissue gas
saturation sufficient for the evolution of
nitrogen bubbles (Jepson et al., 2003;
´
Fernandez et al., 2005; Fernandez et al.,
2012). In this scenario, the rate of ascent
would need to be sufficiently rapid to
compromise behavioral or physiological
protections against nitrogen bubble
formation. Alternatively, Tyack et al.
(2006) studied the deep diving behavior
of beaked whales and concluded that:
‘‘Using current models of breath-hold
diving, we infer that their natural diving
behavior is inconsistent with known
problems of acute nitrogen
supersaturation and embolism.’’
Collectively, these hypotheses can be
referred to as ‘‘hypotheses of
acoustically mediated bubble growth.’’
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Although theoretical predictions
suggest the possibility for acoustically
mediated bubble growth, there is
considerable disagreement among
scientists as to its likelihood (Piantadosi
and Thalmann, 2004; Evans and Miller,
2003). Crum and Mao (1996)
hypothesized that received levels would
have to exceed 190 dB in order for there
to be the possibility of significant
bubble growth due to supersaturation of
gases in the blood (i.e., rectified
diffusion). More recent work conducted
by Crum et al. (2005) demonstrated the
possibility of rectified diffusion for
short duration signals, but at SELs and
tissue saturation levels that are highly
improbable to occur in diving marine
mammals. To date, energy levels (ELs)
predicted to cause in vivo bubble
formation within diving cetaceans have
not been evaluated (NOAA, 2002b).
Although it has been argued that
traumas from some recent beaked whale
strandings are consistent with gas
emboli and bubble-induced tissue
separations (Jepson et al., 2003), there is
no conclusive evidence of this.
However, Jepson et al. (2003, 2005) and
Fernandez et al. (2004, 2005, 2012)
concluded that in vivo bubble
formation, which may be exacerbated by
deep, long-duration, repetitive dives
may explain why beaked whales appear
to be particularly vulnerable to sonar
exposures. Further investigation is
needed to further assess the potential
validity of these hypotheses.
Acoustic Masking
Marine mammals use acoustic signals
for a variety of purposes, which differ
among species, but include
communication between individuals,
navigation, foraging, reproduction, and
learning about their environment (Erbe
and Farmer, 2000; Tyack, 2000).
Masking, or auditory interference,
generally occurs when sounds in the
environment are louder than and of a
similar frequency to, auditory signals an
animal is trying to receive. Masking is
a phenomenon that affects animals that
are trying to receive acoustic
information about their environment,
including sounds from other members
of their species, predators, prey, and
sounds that allow them to orient in their
environment. Masking these acoustic
signals can disturb the behavior of
individual animals, groups of animals,
or entire populations.
The extent of the masking interference
depends on the spectral, temporal, and
spatial relationships between the signals
an animal is trying to receive and the
masking noise, in addition to other
factors. In humans, significant masking
of tonal signals occurs as a result of
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exposure to noise in a narrow band of
similar frequencies. As the sound level
increases, though, the detection of
frequencies above those of the masking
stimulus decreases also. This principle
is expected to apply to marine mammals
as well because of common
biomechanical cochlear properties
across taxa.
Richardson et al. (1995b) argued that
the maximum radius of influence of an
industrial noise (including broadband
low frequency sound transmission) on a
marine mammal is the distance from the
source to the point at which the noise
can barely be heard. This range is
determined by either the hearing
sensitivity of the animal or the
background noise level present.
Industrial masking is most likely to
affect some species’ ability to detect
communication calls and natural
sounds (i.e., surf noise, prey noise, etc.;
Richardson et al., 1995).
The echolocation calls of toothed
whales are subject to masking by high
frequency sound. Human data indicate
low-frequency sound can mask highfrequency sounds (i.e., upward
masking). Studies on captive
odontocetes by Au et al. (1974, 1985,
1993) indicate that some species may
use various processes to reduce masking
effects (e.g., adjustments in echolocation
call intensity or frequency as a function
of background noise conditions). There
is also evidence that the directional
hearing abilities of odontocetes are
useful in reducing masking at the highfrequencies these cetaceans use to
echolocate, but not at the low-tomoderate frequencies they use to
communicate (Zaitseva et al., 1980). A
recent study by Nachtigall and Supin
(2008) showed that false killer whales
adjust their hearing to compensate for
ambient sounds and the intensity of
returning echolocation signals.
As mentioned previously, the
functional hearing ranges of odontocetes
and pinnipeds underwater overlap the
frequencies of the high-frequency sonar
source (i.e., AN/SQQ–32) used in the
Navy’s training exercises. Additionally,
species’ vocal repertoires span across
the frequencies of the sonar source used
by the Navy. The closer the
characteristics of the masking signal to
the signal of interest, the more likely
masking is to occur. For hull-mounted
and towed sonar the pulse length and
low duty cycle of the HFAS signal
makes it less likely that masking would
occur as a result. Further, the frequency
band of the sonar is narrow, limiting the
likelihood of auditory masking.
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Impaired Communication
Stress Responses
In addition to making it more difficult
for animals to perceive acoustic cues in
their environment, anthropogenic sound
presents separate challenges for animals
that are vocalizing. When they vocalize,
animals are aware of environmental
conditions that affect the ‘‘active space’’
of their vocalizations, which is the
maximum area within which their
vocalizations can be detected before it
drops to the level of ambient noise
(Brenowitz, 2004; Brumm et al., 2004;
Lohr et al., 2003). Animals are also
aware of environmental conditions that
affect whether listeners can discriminate
and recognize their vocalizations from
other sounds, which is more important
than simply detecting that a
vocalization is occurring (Brenowitz,
1982; Brumm et al., 2004; Dooling,
2004, Marten and Marler, 1977;
Patricelli et al., 2006). Most animals that
vocalize have evolved with an ability to
make adjustments to their vocalizations
to increase the signal-to-noise ratio,
active space, and recognizability/
distinguishability of their vocalizations
in the face of temporary changes in
background noise (Brumm et al., 2004;
Patricelli et al., 2006). Vocalizing
animals can make adjustments to
vocalization characteristics such as the
frequency structure, amplitude,
temporal structure, and temporal
delivery.
Many animals will combine several of
these strategies to compensate for high
levels of background noise.
Anthropogenic sounds that reduce the
signal-to-noise ratio of animal
vocalizations, increase the masked
auditory thresholds of animals listening
for such vocalizations, or reduce the
active space of an animal’s vocalizations
impair communication between
animals. Most animals that vocalize
have evolved strategies to compensate
for the effects of short-term or temporary
increases in background or ambient
noise on their songs or calls. Although
the fitness consequences of these vocal
adjustments remain unknown, like most
other trade-offs animals must make,
some of these strategies probably come
at a cost (Patricelli et al., 2006). For
example, vocalizing more loudly in
noisy environments may have energetic
costs that decrease the net benefits of
vocal adjustment and alter a bird’s
energy budget (Brumm, 2004; Wood and
Yezerinac, 2006). Shifting songs and
calls to higher frequencies may also
impose energetic costs (Lambrechts,
1996).
Classic stress responses begin when
an animal’s central nervous system
perceives a potential threat to its
homeostasis. That perception triggers
stress responses regardless of whether a
stimulus actually threatens the animal;
the mere perception of a threat is
sufficient to trigger a stress response
(Moberg, 2000; Sapolsky et al., 2005;
Seyle, 1950). Once an animal’s central
nervous system perceives a threat, it
mounts a biological response or defense
that consists of a combination of the
four general biological defense
responses: behavioral responses,
autonomic nervous system responses,
neuroendocrine responses, or immune
responses.
In the case of many stressors, an
animal’s first and sometimes most
economical (in terms of biotic costs)
response is behavioral avoidance of the
potential stressor or avoidance of
continued exposure to a stressor. An
animal’s second line of defense to
stressors involves the sympathetic part
of the autonomic nervous system and
the classical ‘‘fight or flight’’ response
which includes the cardiovascular
system, the gastrointestinal system, the
exocrine glands, and the adrenal
medulla to produce changes in heart
rate, blood pressure, and gastrointestinal
activity that humans commonly
associate with ‘‘stress.’’ These responses
have a relatively short duration and may
or may not have significant long-term
effect on an animal’s welfare.
An animal’s third line of defense to
stressors involves its neuroendocrine
systems; the system that has received
the most study has been the
hypothalamus-pituitary-adrenal system
(also known as the HPA axis in
mammals or the hypothalamuspituitary-interrenal axis in fish and
some reptiles). Unlike stress responses
associated with the autonomic nervous
system, virtually all neuro-endocrine
functions that are affected by stress—
including immune competence,
reproduction, metabolism, and
behavior—are regulated by pituitary
hormones. Stress-induced changes in
the secretion of pituitary hormones have
been implicated in failed reproduction
(Moberg, 1987; Rivier, 1995), altered
metabolism (Elasser et al., 2000),
reduced immune competence (Blecha,
2000), and behavioral disturbance.
Increases in the circulation of
glucocorticosteroids (cortisol,
corticosterone, and aldosterone in
marine mammals; see Romano et al.,
2004) have been equated with stress for
many years.
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The primary distinction between
stress (which is adaptive and does not
normally place an animal at risk) and
distress is the biotic cost of the
response. During a stress response, an
animal uses glycogen stores that can be
quickly replenished once the stress is
alleviated. In such circumstances, the
cost of the stress response would not
pose a risk to the animal’s welfare.
However, when an animal does not have
sufficient energy reserves to satisfy the
energetic costs of a stress response,
energy resources must be diverted from
other biotic function, which impairs
those functions that experience the
diversion. For example, when mounting
a stress response diverts energy away
from growth in young animals, those
animals may experience stunted growth.
When mounting a stress response
diverts energy from a fetus, an animal’s
reproductive success and its fitness will
suffer. In these cases, the animals will
have entered a pre-pathological or
pathological state which is called
‘‘distress’’ (Seyle, 1950) or ‘‘allostatic
loading’’ (McEwen and Wingfield,
2003). This pathological state will last
until the animal replenishes its biotic
reserves sufficient to restore normal
function. Note that these examples
involved a long-term (days or weeks)
stress response exposure to stimuli.
Relationships between these
physiological mechanisms, animal
behavior, and the costs of stress
responses have also been documented
fairly well through controlled
experiments; because this physiology
exists in every vertebrate that has been
studied, it is not surprising that stress
responses and their costs have been
documented in both laboratory and freeliving animals (for examples see,
Holberton et al., 1996; Hood et al., 1998;
Jessop et al., 2003; Krausman et al.,
2004; Lankford et al., 2005; Reneerkens
et al., 2002; Thompson and Hamer,
2000). Information has also been
collected on the physiological responses
of marine mammals to exposure to
anthropogenic sounds (Fair and Becker,
2000; Romano et al., 2002; Wright et al.,
2008). For example, Rolland et al.
(2012) found that noise reduction from
reduced ship traffic in the Bay of Fundy
was associated with decreased stress in
North Atlantic right whales. In a
conceptual model developed by the
Population Consequences of Acoustic
Disturbance (PCAD) working group,
serum hormones were identified as
possible indicators of behavioral effects
that are translated into altered rates of
reproduction and mortality. The Office
of Naval Research hosted a workshop
(Effects of Stress on Marine Mammals
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Exposed to Sound) in 2009 that focused
on this very topic (ONR, 2009).
Studies of other marine animals and
terrestrial animals would also lead us to
expect some marine mammals to
experience physiological stress
responses and, perhaps, physiological
responses that would be classified as
‘‘distress’’ upon exposure to high
frequency, mid-frequency and lowfrequency sounds. For example, Jansen
(1998) reported on the relationship
between acoustic exposures and
physiological responses that are
indicative of stress responses in humans
(for example, elevated respiration and
increased heart rates). Jones (1998)
reported on reductions in human
performance when faced with acute,
repetitive exposures to acoustic
disturbance. Trimper et al. (1998)
reported on the physiological stress
responses of osprey to low-level aircraft
noise while Krausman et al. (2004)
reported on the auditory and physiology
stress responses of endangered Sonoran
pronghorn to military overflights. Smith
et al. (2004a, 2004b), for example,
identified noise-induced physiological
transient stress responses in hearingspecialist fish (i.e., goldfish) that
accompanied short- and long-term
hearing losses. Welch and Welch (1970)
reported physiological and behavioral
stress responses that accompanied
damage to the inner ears of fish and
several mammals.
Hearing is one of the primary senses
marine mammals use to gather
information about their environment
and to communicate with conspecifics.
Although empirical information on the
relationship between sensory
impairment (TTS, PTS, and acoustic
masking) on marine mammals remains
limited, it seems reasonable to assume
that reducing an animal’s ability to
gather information about its
environment and to communicate with
other members of its species would be
stressful for animals that use hearing as
their primary sensory mechanism.
Therefore, we assume that acoustic
exposures sufficient to trigger onset PTS
or TTS would be accompanied by
physiological stress responses because
terrestrial animals exhibit those
responses under similar conditions
(NRC, 2003). More importantly, marine
mammals might experience stress
responses at received levels lower than
those necessary to trigger onset TTS.
Based on empirical studies of the time
required to recover from stress
responses (Moberg, 2000), we also
assume that stress responses are likely
to persist beyond the time interval
required for animals to recover from
TTS and might result in pathological
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and pre-pathological states that would
be as significant as behavioral responses
to TTS.
Behavioral Disturbance
Behavioral responses to sound are
highly variable and context-specific.
Many different variables can influence
an animal’s perception of and response
to (nature and magnitude) an acoustic
event. An animal’s prior experience
with a sound or sound source effects
whether it is less likely (habituation) or
more likely (sensitization) to respond to
certain sounds in the future (animals
can also be innately pre-disposed to
respond to certain sounds in certain
ways) (Southall et al., 2007). Related to
the sound itself, the perceived nearness
of the sound, bearing of the sound
(approaching vs. retreating), similarity
of a sound to biologically relevant
sounds in the animal’s environment
(i.e., calls of predators, prey, or
conspecifics), and familiarity of the
sound may affect the way an animal
responds to the sound (Southall et al.,
2007). Individuals (of different age,
gender, reproductive status, etc.) among
most populations will have variable
hearing capabilities, and differing
behavioral sensitivities to sounds that
will be affected by prior conditioning,
experience, and current activities of
those individuals. Often, specific
acoustic features of the sound and
contextual variables (i.e., proximity,
duration, or recurrence of the sound or
the current behavior that the marine
mammal is engaged in or its prior
experience), as well as entirely separate
factors such as the physical presence of
a nearby vessel, may be more relevant
to the animal’s response than the
received level alone.
Exposure of marine mammals to
sound sources can result in no response
or responses including, but not limited
to: Increased alertness; orientation or
attraction to a sound source; vocal
modifications; cessation of feeding;
cessation of social interaction; alteration
of movement or diving behavior; habitat
abandonment (temporary or permanent);
and, in severe cases, panic, flight,
stampede, or stranding, potentially
resulting in death (Southall et al., 2007).
A review of marine mammal responses
to anthropogenic sound was first
conducted by Richardson and others in
1995. A more recent review (Nowacek et
al., 2007) addresses studies conducted
since 1995 and focuses on observations
where the received sound level of the
exposed marine mammal(s) was known
or could be estimated. The following
sub-sections provide examples of
behavioral responses that provide an
idea of the variability in behavioral
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responses that would be expected given
the differential sensitivities of marine
mammal species to sound and the wide
range of potential acoustic sources to
which a marine mammal may be
exposed. Estimates of the types of
behavioral responses that could occur
for a given sound exposure should be
determined from the literature that is
available for each species, or
extrapolated from closely related
species when no information exists.
Flight Response—A flight response is
a dramatic change in normal movement
to a directed and rapid movement away
from the perceived location of a sound
source. Relatively little information on
flight responses of marine mammals to
anthropogenic signals exist, although
observations of flight responses to the
presence of predators have occurred
(Connor and Heithaus, 1996). Flight
responses have been speculated as being
a component of marine mammal
strandings associated with sonar
activities (Evans and England, 2001).
Response to Predator—Evidence
suggests that at least some marine
mammals have the ability to
acoustically identify potential predators.
For example, harbor seals that reside in
the coastal waters off British Columbia
are frequently targeted by certain groups
of killer whales, but not others. The
seals discriminate between the calls of
threatening and non-threatening killer
whales (Deecke et al., 2002), a capability
that should increase survivorship while
reducing the energy required for
attending to and responding to all killer
whale calls. The occurrence of masking
or hearing impairment provides a means
by which marine mammals may be
prevented from responding to the
acoustic cues produced by their
predators. Whether or not this is a
possibility depends on the duration of
the masking/hearing impairment and
the likelihood of encountering a
predator during the time that predator
cues are impeded.
Diving—Changes in dive behavior can
vary widely. They may consist of
increased or decreased dive times and
surface intervals as well as changes in
the rates of ascent and descent during a
dive. Variations in dive behavior may
reflect interruptions in biologically
significant activities (e.g., foraging) or
they may be of little biological
significance. Variations in dive behavior
may also expose an animal to
potentially harmful conditions (e.g.,
increasing the chance of ship-strike) or
may serve as an avoidance response that
enhances survivorship. The impact of a
variation in diving resulting from an
acoustic exposure depends on what the
animal is doing at the time of the
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exposure and the type and magnitude of
the response.
Nowacek et al. (2004) reported
disruptions of dive behaviors in foraging
North Atlantic right whales when
exposed to an alerting stimulus, an
action, they noted, that could lead to an
increased likelihood of ship strike.
However, the whales did not respond to
playbacks of either right whale social
sounds or vessel noise, highlighting the
importance of the sound characteristics
in producing a behavioral reaction.
Conversely, Indo-Pacific humpback
dolphins have been observed to dive for
longer periods of time in areas where
vessels were present and/or
approaching (Ng and Leung, 2003). In
both of these studies, the influence of
the sound exposure cannot be
decoupled from the physical presence of
a surface vessel, thus complicating
interpretations of the relative
contribution of each stimulus to the
response. Indeed, the presence of
surface vessels, their approach, and
speed of approach, seemed to be
significant factors in the response of the
Indo-Pacific humpback dolphins (Ng
and Leung, 2003). Low frequency
signals of the Acoustic Thermometry of
Ocean Climate (ATOC) sound source
were not found to affect dive times of
humpback whales in Hawaiian waters
(Frankel and Clark, 2000) or to overtly
affect elephant seal dives (Costa et al.,
2003). They did, however, produce
subtle effects that varied in direction
and degree among the individual seals,
illustrating the equivocal nature of
behavioral effects and consequent
difficulty in defining and predicting
them.
Due to past incidents of beaked whale
strandings associated with sonar
operations, feedback paths are provided
between avoidance and diving and
indirect tissue effects. This feedback
accounts for the hypothesis that
variations in diving behavior and/or
avoidance responses can possibly result
in nitrogen tissue supersaturation and
nitrogen off-gassing, possibly to the
point of deleterious vascular bubble
formation (Jepson et al., 2003).
Although hypothetical, discussions
surrounding this potential process are
controversial.
Foraging—Disruption of feeding
behavior can be difficult to correlate
with anthropogenic sound exposure, so
it is usually inferred by observed
displacement from known foraging
areas, the appearance of secondary
indicators (e.g., bubble nets or sediment
plumes), or changes in dive behavior.
Noise from seismic surveys was not
found to impact the feeding behavior in
western grey whales off the coast of
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Russia (Yazvenko et al., 2007) and
sperm whales engaged in foraging dives
did not abandon dives when exposed to
distant signatures of seismic airguns
(Madsen et al., 2006). However, Miller
et al. (2009) reported buzz rates (a proxy
for feeding) 19 percent lower during
exposure to distant signatures of seismic
airguns. Balaenopterid whales exposed
to moderate low-frequency signals
similar to the ATOC sound source
demonstrated no variation in foraging
activity (Croll et al., 2001), whereas five
out of six North Atlantic right whales
exposed to an acoustic alarm
interrupted their foraging dives
(Nowacek et al., 2004). Although the
received sound pressure levels were
similar in the latter two studies, the
frequency, duration, and temporal
pattern of signal presentation were
different. These factors, as well as
differences in species sensitivity, are
likely contributing factors to the
differential response. Blue whales
exposed to simulated mid-frequency
sonar in the Southern California Bight
were less likely to produce low
frequency calls usually associated with
´
feeding behavior (Melcon et al., 2012).
It is not known whether the lower rates
of calling actually indicated a reduction
in feeding behavior or social contact
since the study used data from remotely
deployed, passive acoustic monitoring
buoys. In contrast, blue whales
increased their likelihood of calling
when ship noise was present, and
decreased their likelihood of calling in
the presence of explosive noise,
although this result was not statistically
´
significant (Melcon et al., 2012).
Additionally, the likelihood of an
animal calling decreased with the
increased received level of midfrequency sonar, beginning at a SPL of
approximately 110–120 dB re 1 mPa
´
(Melcon et al., 2012). Preliminary
results from the 2010–2011 field season
of an ongoing behavioral response study
in Southern California waters indicated
that, in some cases and at low received
levels, tagged blue whales responded to
mid-frequency sonar but that those
responses were mild and there was a
quick return to their baseline activity
(Southall et al., 2011). A determination
of whether foraging disruptions incur
fitness consequences will require
information on or estimates of the
energetic requirements of the
individuals and the relationship
between prey availability, foraging effort
and success, and the life history stage of
the animal. Goldbogen et al., (2013)
monitored behavioral responses of
tagged blue whales located in feeding
areas when exposed simulated MFA
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sonar. Responses varied depending on
behavioral context, with deep feeding
whales being more significantly affected
(i.e., generalized avoidance; cessation of
feeding; increased swimming speeds; or
directed travel away from the source)
compared to surface feeding individuals
that typically showed no change in
behavior. Non-feeding whales also
seemed to be affected by exposure. The
authors indicate that disruption of
feeding and displacement could impact
individual fitness and health. However,
for this to be true, we would have to
assume that an individual whale could
not compensate for this lost feeding
opportunity by either immediately
feeding at another location, by feeding
shortly after cessation of acoustic
exposure, or by feeding at a later time.
There is no indication this is the case,
particularly since unconsumed prey
would likely still be available in the
environment in most cases following the
cessation of acoustic exposure.
Breathing—Variations in respiration
naturally vary with different behaviors
and variations in respiration rate as a
function of acoustic exposure can be
expected to co-occur with other
behavioral reactions, such as a flight
response or an alteration in diving.
However, respiration rates in and of
themselves may be representative of
annoyance or an acute stress response.
Mean exhalation rates of gray whales at
rest and while diving were found to be
unaffected by seismic surveys
conducted adjacent to the whale feeding
grounds (Gailey et al., 2007). Studies
with captive harbor porpoises showed
increased respiration rates upon
introduction of acoustic alarms
(Kastelein et al., 2001; Kastelein et al.,
2006a) and emissions for underwater
data transmission (Kastelein et al.,
2005). However, exposure of the same
acoustic alarm to a striped dolphin
under the same conditions did not elicit
a response (Kastelein et al., 2006a),
again highlighting the importance in
understanding species differences in the
tolerance of underwater noise when
determining the potential for impacts
resulting from anthropogenic sound
exposure (Southall et al., 2007;
Henderson et al., 2014).
Social Relationships—Social
interactions between mammals can be
affected by noise via the disruption of
communication signals or by the
displacement of individuals. Disruption
of social relationships therefore depends
on the disruption of other behaviors
(e.g., caused avoidance, masking, etc.)
and no specific overview is provided
here. However, social disruptions must
be considered in context of the
relationships that are affected. Long-
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term disruptions of mother/calf pairs or
mating displays have the potential to
affect the growth and survival or
reproductive effort/success of
individuals, respectively.
Vocalizations (also see Masking
Section)—Vocal changes in response to
anthropogenic noise can occur across
the repertoire of sound production
modes used by marine mammals, such
as whistling, echolocation click
production, calling, and singing.
Changes may result in response to a
need to compete with an increase in
background noise or may reflect an
increased vigilance or startle response.
For example, in the presence of lowfrequency active sonar, humpback
whales have been observed to increase
the length of their ‘‘songs’’ (Miller et al.,
2000; Fristrup et al., 2003), possibly due
to the overlap in frequencies between
the whale song and the low-frequency
active sonar. A similar compensatory
effect for the presence of low-frequency
vessel noise has been suggested for right
whales; right whales have been
observed to shift the frequency content
of their calls upward while reducing the
rate of calling in areas of increased
anthropogenic noise (Parks et al., 2007).
Killer whales off the northwestern coast
of the U.S. have been observed to
increase the duration of primary calls
once a threshold in observing vessel
density (e.g., whale watching) was
reached, which has been suggested as a
response to increased masking noise
produced by the vessels (Foote et al.,
2004; NOAA, 2014b). In contrast, both
sperm and pilot whales potentially
ceased sound production during the
Heard Island feasibility test (Bowles et
al., 1994), although it cannot be
absolutely determined whether the
inability to acoustically detect the
animals was due to the cessation of
sound production or the displacement
of animals from the area.
Avoidance—Avoidance is the
displacement of an individual from an
area as a result of the presence of a
sound. Richardson et al., (1995) noted
that avoidance reactions are the most
obvious manifestations of disturbance in
marine mammals. It is qualitatively
different from the flight response, but
also differs in the magnitude of the
response (i.e., directed movement, rate
of travel, etc.). Oftentimes avoidance is
temporary, and animals return to the
area once the noise has ceased. Longer
term displacement is possible, however,
which can lead to changes in abundance
or distribution patterns of the species in
the affected region if they do not
become acclimated to the presence of
the sound (Blackwell et al., 2004; Bejder
et al., 2006; Teilmann et al., 2006).
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Acute avoidance responses have been
observed in captive porpoises and
pinnipeds exposed to a number of
different sound sources (Kastelein et al.,
2001; Finneran et al., 2003; Kastelein et
al., 2006a; Kastelein et al., 2006b).
Short-term avoidance of seismic
surveys, low frequency emissions, and
acoustic deterrents have also been noted
in wild populations of odontocetes
(Bowles et al., 1994; Goold, 1996; 1998;
Stone et al., 2000; Morton and
Symonds, 2002) and to some extent in
mysticetes (Gailey et al., 2007), while
longer term or repetitive/chronic
displacement for some dolphin groups
and for manatees has been suggested to
be due to the presence of chronic vessel
noise (Haviland-Howell et al., 2007;
Miksis-Olds et al., 2007).
Maybaum (1993) conducted sound
playback experiments to assess the
effects of MFAS on humpback whales in
Hawaiian waters. Specifically, she
exposed focal pods to sounds of a 3.3kHz sonar pulse, a sonar frequency
sweep from 3.1 to 3.6 kHz, and a control
(blank) tape while monitoring behavior,
movement, and underwater
vocalizations. The two types of sonar
signals (which both contained mid- and
low-frequency components) differed in
their effects on the humpback whales,
but both resulted in avoidance behavior.
The whales responded to the pulse by
increasing their distance from the sound
source and responded to the frequency
sweep by increasing their swimming
speeds and track linearity. In the
Caribbean, sperm whales avoided
exposure to mid-frequency submarine
sonar pulses, in the range of 1000 Hz to
10,000 Hz (IWC 2005).
Kvadsheim et al., (2007) conducted a
controlled exposure experiment in
which killer whales fitted with D-tags
were exposed to mid-frequency active
sonar (Source A: a 1.0 second upsweep
209 dB @1–2 kHz every 10 seconds for
10 minutes; Source B: with a 1.0 second
upsweep 197 dB @6–7 kHz every 10
seconds for 10 minutes). When exposed
to Source A, a tagged whale and the
group it was traveling with did not
appear to avoid the source. When
exposed to Source B, the tagged whales
along with other whales that had been
carousel feeding, ceased feeding during
the approach of the sonar and moved
rapidly away from the source. When
exposed to Source B, Kvadsheim and
his co-workers reported that a tagged
killer whale seemed to try to avoid
further exposure to the sound field by
the following behaviors: immediately
swimming away (horizontally) from the
source of the sound; engaging in a series
of erratic and frequently deep dives that
seemed to take it below the sound field;
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or swimming away while engaged in a
series of erratic and frequently deep
dives. Although the sample sizes in this
study are too small to support statistical
analysis, the behavioral responses of the
orcas were consistent with the results of
other studies.
In 2007, the first in a series of
behavioral response studies, a
collaboration by the Navy, NMFS, and
other scientists showed one beaked
whale (Mesoplodon densirostris)
responding to an MFAS playback. Tyack
et al. (2011) indicates that the playback
began when the tagged beaked whale
was vocalizing at depth (at the deepest
part of a typical feeding dive), following
a previous control with no sound
exposure. The whale appeared to stop
clicking significantly earlier than usual,
when exposed to mid-frequency signals
in the 130–140 dB (rms) received level
range. After a few more minutes of the
playback, when the received level
reached a maximum of 140–150 dB, the
whale ascended on the slow side of
normal ascent rates with a longer than
normal ascent, at which point the
exposure was terminated. The results
are from a single experiment and a
greater sample size is needed before
robust and definitive conclusions can be
drawn.
Tyack et al. (2011) also indicates that
Blainville’s beaked whales appear to be
sensitive to noise at levels well below
expected TTS (∼160 dB re 1 mPa). This
sensitivity is manifest by an adaptive
movement away from a sound source.
This response was observed irrespective
of whether the signal transmitted was
within the band width of MFAS, which
suggests that beaked whales may not
respond to the specific sound
signatures. Instead, they may be
sensitive to any pulsed sound from a
point source in this frequency range.
The response to such stimuli appears to
involve maximizing the distance from
the sound source.
Stimpert et al. (2014) tagged a Baird’s
beaked whale, which was subsequently
exposed to simulated mid-frequency
sonar. Changes in the animal’s dive
behavior and locomotion were observed
when received level reached 127 dB re
1 mPa.
Results from a 2007–2008 study
conducted near the Bahamas showed a
change in diving behavior of an adult
Blainville’s beaked whale to playback of
mid-frequency source and predator
sounds (Boyd et al., 2008; Southall et al.
2009; Tyack et al., 2011). Reaction to
mid-frequency sounds included
premature cessation of clicking and
termination of a foraging dive, and a
slower ascent rate to the surface. Results
from a similar behavioral response
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study in southern California waters have
been presented for the 2010–2011 field
season (Southall et al. 2011; DeRuiter et
al., 2013b). DeRuiter et al. (2013b)
presented results from two Cuvier’s
beaked whales that were tagged and
exposed to simulated mid-frequency
active sonar during the 2010 and 2011
field seasons of the southern California
behavioral response study. The 2011
whale was also incidentally exposed to
mid-frequency active sonar from a
distant naval exercise. Received levels
from the mid-frequency active sonar
signals from the controlled and
incidental exposures were calculated as
84–144 and 78–106 dB re 1 mPa root
mean square (rms), respectively. Both
whales showed responses to the
controlled exposures, ranging from
initial orientation changes to avoidance
responses characterized by energetic
fluking and swimming away from the
source. However, the authors did not
detect similar responses to incidental
exposure to distant naval sonar
exercises at comparable received levels,
indicating that context of the exposures
(e.g., source proximity, controlled
source ramp-up) may have been a
significant factor. Cuvier’s beaked whale
responses suggested particular
sensitivity to sound exposure as
consistent with results for Blainville’s
beaked whale. Similarly, beaked whales
exposed to sonar during British training
exercises stopped foraging (DSTL,
2007), and preliminary results of
controlled playback of sonar may
indicate feeding/foraging disruption of
killer whales and sperm whales (Miller
et al., 2011).
In the 2007–2008 Bahamas study,
playback sounds of a potential
predator—a killer whale—resulted in a
similar but more pronounced reaction,
which included longer inter-dive
intervals and a sustained straight-line
departure of more than 20 km from the
area. The authors noted, however, that
the magnified reaction to the predator
sounds could represent a cumulative
effect of exposure to the two sound
types since killer whale playback began
approximately 2 hours after midfrequency source playback. Pilot whales
and killer whales off Norway also
exhibited horizontal avoidance of a
transducer with outputs in the midfrequency range (signals in the 1–2 kHz
and 6–7 kHz ranges) (Miller et al., 2011).
Additionally, separation of a calf from
its group during exposure to midfrequency sonar playback was observed
on one occasion (Miller et al., 2011). In
contrast, preliminary analyses suggest
that none of the pilot whales or false
killer whales in the Bahamas showed an
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53669
avoidance response to controlled
exposure playbacks (Southall et al.,
2009).
Through analysis of the behavioral
response studies, a preliminary
overarching effect of greater sensitivity
to all anthropogenic exposures was seen
in beaked whales compared to the other
odontocetes studied (Southall et al.,
2009). Therefore, recent studies have
focused specifically on beaked whale
responses to active sonar transmissions
or controlled exposure playback of
simulated sonar on various military
ranges (Defence Science and
Technology Laboratory, 2007; Claridge
and Durban, 2009; Moretti et al., 2009;
McCarthy et al., 2011; Tyack et al.,
2011). In the Bahamas, Blainville’s
beaked whales located on the range will
move off-range during sonar use and
return only after the sonar transmissions
have stopped, sometimes taking several
days to do so (Claridge and Durban
2009; Moretti et al., 2009; McCarthy et
al., 2011; Tyack et al., 2011). Moretti et
al. (2014) used recordings from seafloormounted hydrophones at the Atlantic
Undersea Test and Evaluation Center
(AUTEC) to analyze the probability of
Blainsville’s beaked whale dives before,
during, and after Navy sonar exercises.
Orientation—A shift in an animal’s
resting state or an attentional change via
an orienting response represent
behaviors that would be considered
mild disruptions if occurring alone. As
previously mentioned, the responses
may co-occur with other behaviors; for
instance, an animal may initially orient
toward a sound source, and then move
away from it. Thus, any orienting
response should be considered in
context of other reactions that may
occur.
Behavioral Responses
Southall et al. (2007) reports the
results of the efforts of a panel of experts
in acoustic research from behavioral,
physiological, and physical disciplines
that convened and reviewed the
available literature on marine mammal
hearing and physiological and
behavioral responses to human-made
sound with the goal of proposing
exposure criteria for certain effects. This
peer-reviewed compilation of literature
is very valuable, though Southall et al.
(2007) note that not all data are equal,
some have poor statistical power,
insufficient controls, and/or limited
information on received levels,
background noise, and other potentially
important contextual variables—such
data were reviewed and sometimes used
for qualitative illustration but were not
included in the quantitative analysis for
the criteria recommendations. All of the
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studies considered, however, contain an
estimate of the received sound level
when the animal exhibited the indicated
response.
In the Southall et al. (2007)
publication, for the purposes of
analyzing responses of marine mammals
to anthropogenic sound and developing
criteria, the authors differentiate
between single pulse sounds, multiple
pulse sounds, and non-pulse sounds.
MFAS/HFAS sonar is considered a nonpulse sound. Southall et al. (2007)
summarize the studies associated with
low-frequency, mid-frequency, and
high-frequency cetacean and pinniped
responses to non-pulse sounds, based
strictly on received level, in Appendix
C of their article (incorporated by
reference and summarized in the three
paragraphs below).
The studies that address responses of
low-frequency cetaceans to non-pulse
sounds include data gathered in the
field and related to several types of
sound sources (of varying similarity to
MFAS/HFAS) including: Vessel noise,
drilling and machinery playback, lowfrequency M-sequences (sine wave with
multiple phase reversals) playback,
tactical low-frequency active sonar
playback, drill ships, Acoustic
Thermometry of Ocean Climate (ATOC)
source, and non-pulse playbacks. These
studies generally indicate no (or very
limited) responses to received levels in
the 90 to 120 dB re: 1 mPa range and an
increasing likelihood of avoidance and
other behavioral effects in the 120 to
160 dB range. As mentioned earlier,
though, contextual variables play a very
important role in the reported responses
and the severity of effects are not linear
when compared to received level. Also,
few of the laboratory or field datasets
had common conditions, behavioral
contexts or sound sources, so it is not
surprising that responses differ.
The studies that address responses of
mid-frequency cetaceans to non-pulse
sounds include data gathered both in
the field and the laboratory and related
to several different sound sources (of
varying similarity to MFAS/HFAS)
including: pingers, drilling playbacks,
ship and ice-breaking noise, vessel
noise, Acoustic Harassment Devices
(AHDs), Acoustic Deterrent Devices
(ADDs), MFAS, and non-pulse bands
and tones. Southall et al. (2007) were
unable to come to a clear conclusion
regarding the results of these studies. In
some cases, animals in the field showed
significant responses to received levels
between 90 and 120 dB, while in other
cases these responses were not seen in
the 120 to 150 dB range. The disparity
in results was likely due to contextual
variation and the differences between
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the results in the field and laboratory
data (animals typically responded at
lower levels in the field).
The studies that address responses of
high frequency cetaceans to non-pulse
sounds include data gathered both in
the field and the laboratory and related
to several different sound sources (of
varying similarity to MFAS/HFAS)
including: pingers, AHDs, and various
laboratory non-pulse sounds. All of
these data were collected from harbor
porpoises. Southall et al. (2007)
concluded that the existing data
indicate that harbor porpoises are likely
sensitive to a wide range of
anthropogenic sounds at low received
levels (∼ 90 to 120 dB), at least for initial
exposures. All recorded exposures
above 140 dB induced profound and
sustained avoidance behavior in wild
harbor porpoises (Southall et al., 2007).
Rapid habituation was noted in some
but not all studies. There is no data to
indicate whether other high frequency
cetaceans are as sensitive to
anthropogenic sound as harbor
porpoises are.
The studies that address the responses
of pinnipeds in water to non-pulse
sounds include data gathered both in
the field and the laboratory and related
to several different sound sources (of
varying similarity to MFAS/HFAS)
including: AHDs, ATOC, various nonpulse sounds used in underwater data
communication; underwater drilling,
and construction noise. Few studies
exist with enough information to
include them in the analysis. The
limited data suggested that exposures to
non-pulse sounds between 90 and 140
dB generally do not result in strong
behavioral responses in pinnipeds in
water, but no data exist at higher
received levels.
Potential Effects of Behavioral
Disturbance
The different ways that marine
mammals respond to sound are
sometimes indicators of the ultimate
effect that exposure to a given stimulus
will have on the well-being (survival,
reproduction, etc.) of an animal. There
is limited marine mammal data
quantitatively relating the exposure of
marine mammals to sound to effects on
reproduction or survival, though data
exists for terrestrial species to which we
can draw comparisons for marine
mammals.
Attention is the cognitive process of
selectively concentrating on one aspect
of an animal’s environment while
ignoring other things (Posner, 1994).
Because animals (including humans)
have limited cognitive resources, there
is a limit to how much sensory
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information they can process at any
time. The phenomenon called
‘‘attentional capture’’ occurs when a
stimulus (usually a stimulus that an
animal is not concentrating on or
attending to) ‘‘captures’’ an animal’s
attention. This shift in attention can
occur consciously or subconsciously
(for example, when an animal hears
sounds that it associates with the
approach of a predator) and the shift in
attention can be sudden (Dukas, 2002;
van Rij, 2007). Once a stimulus has
captured an animal’s attention, the
animal can respond by ignoring the
stimulus, assuming a ‘‘watch and wait’’
posture, or treat the stimulus as a
disturbance and respond accordingly,
which includes scanning for the source
of the stimulus or ‘‘vigilance’’
(Cowlishaw et al., 2004).
Vigilance is normally an adaptive
behavior that helps animals determine
the presence or absence of predators,
assess their distance from conspecifics,
or to attend cues from prey (Bednekoff
and Lima, 1998; Treves, 2000). Despite
those benefits, however, vigilance has a
cost of time; when animals focus their
attention on specific environmental
cues, they are not attending to other
activities such as foraging. These costs
have been documented best in foraging
animals, where vigilance has been
shown to substantially reduce feeding
rates (Saino, 1994; Beauchamp and
Livoreil, 1997; Fritz et al., 2002).
Animals will spend more time being
vigilant, which may translate to less
time foraging or resting, when
disturbance stimuli approach them
more directly, remain at closer
distances, have a greater group size (for
example, multiple surface vessels), or
when they co-occur with times that an
animal perceives increased risk (for
example, when they are giving birth or
accompanied by a calf). Most of the
published literature, however, suggests
that direct approaches will increase the
amount of time animals will dedicate to
being vigilant. For example, bighorn
sheep and Dall’s sheep dedicated more
time being vigilant, and less time resting
or foraging, when aircraft made direct
approaches over them (Frid, 2001;
Stockwell et al., 1991).
Several authors have established that
long-term and intense disturbance
stimuli can cause population declines
by reducing the body condition of
individuals that have been disturbed,
followed by reduced reproductive
success, reduced survival, or both (Daan
et al., 1996; Madsen, 1994; White,
1983). For example, Madsen (1994)
reported that pink-footed geese in
undisturbed habitat gained body mass
and had about a 46-percent reproductive
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success rate compared with geese in
disturbed habitat (being consistently
scared off the fields on which they were
foraging) which did not gain mass and
had a 17-percent reproductive success
rate. Similar reductions in reproductive
success have been reported for mule
deer disturbed by all-terrain vehicles
(Yarmoloy et al., 1988), caribou
disturbed by seismic exploration blasts
(Bradshaw et al., 1998), caribou
disturbed by low-elevation military jetfights (Luick et al., 1996), and caribou
disturbed by low-elevation jet flights
(Harrington and Veitch, 1992).
Similarly, a study of elk that were
disturbed experimentally by pedestrians
concluded that the ratio of young to
mothers was inversely related to
disturbance rate (Phillips and
Alldredge, 2000).
The primary mechanism by which
increased vigilance and disturbance
appear to affect the fitness of individual
animals is by disrupting an animal’s
time budget and, as a result, reducing
the time they might spend foraging and
resting (which increases an animal’s
activity rate and energy demand). For
example, a study of grizzly bears
reported that bears disturbed by hikers
reduced their energy intake by an
average of 12 kcal/minute (50.2 × 103kJ/
minute), and spent energy fleeing or
acting aggressively toward hikers (White
et al., 1999). Alternately, Ridgway et al.
(2006) reported that increased vigilance
in bottlenose dolphins exposed to sound
over a 5-day period did not cause any
sleep deprivation or stress effects such
as changes in cortisol or epinephrine
levels.
Lusseau and Bejder (2007) present
data from three long-term studies
illustrating the connections between
disturbance from whale-watching boats
and population-level effects in
cetaceans. In Sharks Bay Australia, the
abundance of bottlenose dolphins was
compared within adjacent control and
tourism sites over three consecutive 4.5year periods of increasing tourism
levels. Between the second and third
time periods, in which tourism doubled,
dolphin abundance decreased by 15
percent in the tourism area and did not
change significantly in the control area.
In Fiordland, New Zealand, two
populations (Milford and Doubtful
Sounds) of bottlenose dolphins with
tourism levels that differed by a factor
of seven were observed and significant
increases in travelling time and
decreases in resting time were
documented for both. Consistent shortterm avoidance strategies were observed
in response to tour boats until a
threshold of disturbance was reached
(average 68 minutes between
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interactions), after which the response
switched to a longer term habitat
displacement strategy. For one
population tourism only occurred in a
part of the home range, however,
tourism occurred throughout the home
range of the Doubtful Sound population
and once boat traffic increased beyond
the 68-minute threshold (resulting in
abandonment of their home range/
preferred habitat), reproductive success
drastically decreased (increased
stillbirths) and abundance decreased
significantly (from 67 to 56 individuals
in short period). Last, in a study of
northern resident killer whales off
Vancouver Island, exposure to boat
traffic was shown to reduce foraging
opportunities and increase traveling
time. A simple bioenergetics model was
applied to show that the reduced
foraging opportunities equated to a
decreased energy intake of 18 percent,
while the increased traveling incurred
an increased energy output of 3–4
percent, which suggests that a
management action based on avoiding
interference with foraging might be
particularly effective.
On a related note, many animals
perform vital functions, such as feeding,
resting, traveling, and socializing, on a
diel cycle (24-hour cycle). Substantive
behavioral reactions to noise exposure
(such as disruption of critical life
functions, displacement, or avoidance of
important habitat) are more likely to be
significant if they last more than one
diel cycle or recur on subsequent days
(Southall et al., 2007). Consequently, a
behavioral response lasting less than 1
day and not recurring on subsequent
days is not considered particularly
severe unless it could directly affect
reproduction or survival (Southall et al.,
2007). Note that there is a difference
between multiple-day substantive
behavioral reactions and multiple-day
anthropogenic activities. For example,
just because an at-sea exercise lasts for
multiple days does not necessarily mean
that individual animals are either
exposed to that exercise for multiple
days or, further, exposed in a manner
resulting in a sustained multiple day
substantive behavioral responses.
In order to understand how the effects
of activities may or may not impact
stocks and populations of marine
mammals, it is necessary to understand
not only what the likely disturbances
are going to be, but how those
disturbances may affect the
reproductive success and survivorship
of individuals, and then how those
impacts to individuals translate to
population changes. Following on the
earlier work of a committee of the U.S.
National Research Council (NRC, 2005),
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New et al. (2014), in an effort termed the
Potential Consequences of Disturbance
(PCoD), outline an updated conceptual
model of the relationships linking
disturbance to changes in behavior and
physiology, health, vital rates, and
population dynamics (below). As
depicted, behavioral and physiological
changes can either have direct (acute)
effects on vital rates, such as when
changes in habitat use or increased
stress levels raise the probability of
mother-calf separation or predation, or
they can have indirect and long-term
(chronic) effects on vital rates, such as
when changes in time/energy budgets or
increased disease susceptibility affect
health, which then affects vital rates
(New et al., 2014).
In addition to outlining this general
framework and compiling the relevant
literature that supports it, New et al.
(2014) have chosen four example
species for which extensive long-term
monitoring data exist (southern
elephant seals, North Atlantic right
whales, Ziphidae beaked whales, and
bottlenose dolphins) and developed
state-space energetic models that can be
used to effectively forecast longer-term,
population-level impacts from
behavioral changes. While these are
very specific models with very specific
data requirements that cannot yet be
applied broadly to project-specific risk
assessments, they are a critical first step.
Vessels
Commercial and Navy ship strikes of
cetaceans can cause major wounds,
which may lead to the death of the
animal. An animal at the surface could
be struck directly by a vessel, a
surfacing animal could hit the bottom of
a vessel, or an animal just below the
surface could be cut by a vessel’s
propeller. The severity of injuries
typically depends on the size and speed
of the vessel (Knowlton and Kraus,
2001; Laist et al., 2001; Vanderlaan and
Taggart, 2007).
Marine mammals react to vessels in a
variety of ways. Some respond
negatively by retreating or engaging in
antagonistic responses while other
animals ignore the stimulus altogether
(Terhune and Verboom, 1999; Watkins,
1986). Silber et al. (2010) concludes that
large whales that are in close proximity
to a vessel may not regard the vessel as
a threat, or may be involved in a vital
activity (i.e., mating or feeding) which
may not allow them to have a proper
avoidance response. Cetacean species
generally pay little attention to
transiting vessel traffic as it approaches,
although they may engage in last minute
avoidance maneuvers (Laist et al.,
2001). Baleen whale responses to vessel
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traffic range from avoidance maneuvers
to disinterest in the presence of vessels
(Nowacek et al., 2007; Scheidat et al.,
2004). Species of delphinids can vary
widely in their reaction to vessels. Many
exhibit mostly neutral behavior, but
there are frequent instances of observed
avoidance behaviors (Hewitt, 1985;
¨
Wursig et al., 1998). Many species of
odontocetes (e.g., bottlenose dolphin)
are frequently observed bow riding or
jumping in the wake of a vessel (Norris
and Prescott, 1961; Ritter, 2002; Shane
¨
et al., 1986; Wursig et al., 1998).
The most vulnerable marine mammals
are those that spend extended periods of
time at the surface in order to restore
oxygen levels within their tissues after
deep dives (e.g., the sperm whale). In
addition, some baleen whales, such as
the North Atlantic right whale, seem
generally unresponsive to vessel sound,
making them more susceptible to vessel
collisions (Nowacek et al., 2004). These
species are primarily large, slow moving
whales. Smaller marine mammals (e.g.,
bottlenose dolphin) move quickly
through the water column.
An examination of all known ship
strikes from all shipping sources
(civilian and military) indicates vessel
speed is a principal factor in whether a
vessel strike results in death (Knowlton
and Kraus, 2001; Laist et al., 2001;
Jensen and Silber, 2003; Vanderlaan and
Taggart, 2007). In assessing records in
which vessel speed was known, Laist et
al. (2001) found a direct relationship
between the occurrence of a whale
strike and the speed of the vessel
involved in the collision. The authors
concluded that most deaths occurred
when a vessel was traveling in excess of
13 knots.
Jensen and Silber (2003) detailed 292
records of known or probable ship
strikes of all large whale species from
1975 to 2002. Of these, vessel speed at
the time of collision was reported for 58
cases. Of these cases, 39 (or 67 percent)
resulted in serious injury or death (19 of
those resulted in serious injury as
determined by blood in the water,
propeller gashes or severed tailstock,
and fractured skull, jaw, vertebrae,
hemorrhaging, massive bruising or other
injuries noted during necropsy and 20
resulted in death). Operating speeds of
vessels that struck various species of
large whales ranged from 2 to 51 knots.
The majority (79 percent) of these
strikes occurred at speeds of 13 knots or
greater. The average speed that resulted
in serious injury or death was 18.6
knots. Pace and Silber (2005) found that
the probability of death or serious injury
increased rapidly with increasing vessel
speed. Specifically, the predicted
probability of serious injury or death
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increased from 45 to 75 percent as
vessel speed increased from 10 to 14
knots, and exceeded 90 percent at 17
knots. Higher speeds during collisions
result in greater force of impact and also
appear to increase the chance of severe
injuries or death. While modeling
studies have suggested that
hydrodynamic forces pulling whales
toward the vessel hull increase with
increasing speed (Clyne, 1999;
Knowlton et al., 1995), this is
inconsistent with Silber et al. (2010),
which demonstrated that there is no
such relationship (i.e., hydrodynamic
forces are independent of speed).
The Jensen and Silber (2003) report
notes that the database represents a
minimum number of collisions, because
the vast majority probably goes
undetected or unreported. In contrast,
Navy vessels are likely to detect any
strike that does occur, and they are
required to report all ship strikes
involving marine mammals. Overall, the
percentages of Navy traffic relative to
overall large shipping traffic are very
small (on the order of 2 percent).
Other efforts have been undertaken to
investigate the impact from vessels
(both whale-watching and general vessel
traffic noise) and demonstrated impacts
do occur (Bain, 2002; Erbe, 2002;
Lusseau, 2009; Williams et al., 2006,
2009, 2011b, 2013, 2014a, 2014b; Noren
et al., 2009; Read et al., 2014; Rolland
et al., 2012; Pirotta et al., 2015). This
body of research for the most part has
investigated impacts associated with the
presence of chronic stressors, which
differ significantly from generally
intermittent Navy training and testing
activities. For example, in an analysis of
energy costs to killer whales, Williams
et al. (2009) suggested that whalewatching in the Johnstone Strait
resulted in lost feeding opportunities
due to vessel disturbance, which could
carry higher costs than other measures
of behavioral change might suggest.
Ayres et al. (2012) recently reported on
research in the Salish Sea involving the
measurement of southern resident killer
whale fecal hormones to assess two
potential threats to the species recovery:
Lack of prey (salmon) and impacts to
behavior from vessel traffic. Ayres et al.
(2012) suggested that the lack of prey
overshadowed any population-level
physiological impacts on southern
resident killer whales from vessel
traffic.
The Navy’s Draft EA for 2015 West
Coast Civilian Port Defense training
activities fully addressed the potential
impacts of vessel movement on marine
mammals in the Study Area. The Navy
does not anticipate vessel strikes to
marine mammals within the Study
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Area, nor were takes by injury or
mortality resulting from vessel strike
predicted in the Navy’s analysis. Vessel
strikes within the Study Area are highly
unlikely due to the size,
maneuverability, and speed of the
surface mine countermeasure vessel (the
AVENGER class ship would typically
operate at speeds less than 10 knots (18
km/hour); the generally low likelihood
of occurrence of large whales within the
Study Area; the effectiveness of Navy
lookouts; and the implementation of
mitigation measures described below.
Therefore, takes by injury or mortality
resulting from vessel strikes are not
authorized by NMFS in this proposed
incidental harassment authorization.
However, the Navy has proposed
measures (see Proposed Mitigation) to
mitigate potential impacts to marine
mammals from vessel strike and other
physical disturbance (towed in-water
devices) during training activities in the
Study Area.
Marine Mammal Habitat
The primary source of potential
marine mammal habitat impact is
acoustic exposures resulting from mine
detection and mine neutralization
activities. However, the exposures do
not constitute a long-term physical
alteration of the water column or bottom
topography, as the occurrences are of
limited duration and intermittent in
time.
Marine mammal habitat and prey
species may be temporarily impacted by
acoustic sources associated with the
proposed activities. The potential for
acoustic sources to impact marine
mammal habitat or prey species is
discussed below.
Expected Effects on Habitat
The effects of the introduction of
sound into the environment are
generally considered to have a lesser
impact on marine mammal habitat than
the physical alteration of the habitat.
Acoustic exposures are not expected to
result in long-term physical alteration of
the water column or bottom topography,
as the occurrences are of limited
duration and intermittent in time. The
proposed training activities will only
occur during a two week period, and no
military expended material would be
left as a result of this event.
The ambient underwater noise level
within active shipping areas of Los
Angeles/Long Beach has been estimated
around 140 dB re 1 mPa (Tetra Tech Inc.,
2011). Existing ambient acoustic levels
in non-shipping areas around Terminal
Island in the Port of Long Beach ranged
between 120 dB and 132 dB re 1 mPa
(Tetra Tech Inc., 2011). Additional
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vessel noise, aircraft noise, and
underwater acoustics associated with
the proposed training activities have the
potential to temporarily increase the
noise levels of the Study Area. However,
with ambient levels of noise being
elevated, the additional vessel noise
would likely be masked by the existing
environmental noise and marine species
would not be impacted by the sound of
the vessels or aircraft, but perhaps by
the sight of an approaching vessel or the
shadow of a helicopter.
Noise generated from helicopters is
transient in nature and variable in
intensity. Helicopter sounds contain
dominant tones from the rotors that are
generally below 500 Hz. Helicopters
often radiate more sound forward than
aft. The underwater noise produced is
generally brief when compared with the
duration of audibility in the air. The
sound pressure level from an H–60
helicopter hovering at a 50 ft (15 m)
altitude would be approximately 125 dB
re 1 mPa at 1 m below the water surface,
which is lower than the ambient sound
that has been estimated in and around
the Ports of Los Angeles/Long Beach.
Helicopter flights associated with the
proposed activities could occur at
altitudes as low as 75 to 100 ft (23 to
31 m), and typically last two to four
hours.
Mine warfare sonar employs high
frequencies (above 10 kHz) that
attenuate rapidly in the water, thus
producing only a small area of potential
auditory masking. Odontocetes and
pinnipeds may experience some limited
masking at closer ranges as the
frequency band of many mine warfare
sonar overlaps the hearing and
vocalization abilities of some
odontocetes and pinnipeds; however,
the frequency band of the sonar is
narrow, limiting the likelihood of
auditory masking.
The proposed training activities are of
limited duration and dispersion of the
activities in space and time reduce the
potential for disturbance from shipgenerated noise, helicopter noise, and
acoustic transmissions from the
proposed activities on marine mammals.
The relatively high level of ambient
noise in and near the busy shipping
channels also reduces the potential for
any impact on habitat from the addition
of the platforms associated with the
proposed activities.
Effects on Marine Mammal Prey
Invertebrates—Marine invertebrates
in the Study Area inhabit coastal waters
and benthic habitats, including salt
marshes, kelp forests, and soft
sediments, canyons, and the
continential shelf. The diverse range of
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species include oysters, crabs, worms,
ghost shrimp, snails, sponges, sea fans,
isopods, and stony corals (Chess and
Hobson 1997; Dugan et al. 2000; Proctor
et al. 1980).
Very little is known about sound
detection and use of sound by aquatic
invertebrates (Montgomery et al. 2006;
Popper et al. 2001). Organisms may
detect sound by sensing either the
particle motion or pressure component
of sound, or both. Aquatic invertebrates
probably do not detect pressure since
many are generally the same density as
water and few, if any, have air cavities
that would function like the fish swim
bladder in responding to pressure
(Popper et al. 2001). Many marine
invertebrates, however, have ciliated
‘‘hair’’ cells that may be sensitive to
water movements, such as those caused
by currents or water particle motion
very close to a sound source (Mackie
and Singla 2003). These cilia may allow
invertebrates to sense nearby prey or
predators or help with local navigation.
Marine invertebrates may produce and
use sound in territorial behavior, to
deter predators, to find a mate, and to
pursue courtship (Popper et al. 2001).
Both behavioral and auditory
brainstem response studies suggest that
crustaceans may sense sounds up to 3
kHz, but best sensitivity is likely below
200 Hz (Goodall et al. 1990; Lovell et al.
2005; Lovell et al. 2006). Most
cephalopods (e.g., octopus and squid)
likely sense low-frequency sound below
1,000 Hz, with best sensitivities at lower
frequencies (Mooney et al. 2010;
Packard et al. 1990). A few cephalopods
may sense higher frequencies up to
1,500 Hz (Hu et al. 2009). Squid did not
respond to toothed whale ultrasonic
echolocation clicks at sound pressure
levels ranging from 199 to 226 dB re 1
microPascal peak-to-peak, likely
because these clicks were outside of
squid hearing range (Wilson et al. 2007).
However, squid exhibited alarm
responses when exposed to broadband
sound from an approaching seismic
airgun with received levels exceeding
145 to 150 dB re 1 microPascal root
mean square (McCauley et al. 2000).
It is expected that most marine
invertebrates would not sense highfrequency sonar associated with the
proposed activities. Most marine
invertebrates would not be close enough
to active sonar systems to potentially
experience impacts to sensory
structures. Any marine invertebrate
capable of sensing sound may alter its
behavior if exposed to sonar. Although
acoustic transmissions produced during
the proposed activities may briefly
impact individuals, intermittent
exposures to sonar are not expected to
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impact survival, growth, recruitment, or
reproduction of widespread marine
invertebrate populations.
Fish—The portion of the California
Bight in the vicinity of the Study Area
is a transitional zone between cold and
warm water masses, geographically
separated by Point Conception, and is
highly productive (Leet et al. 2001). The
cold-water of the California Bight is rich
in microscopic plankton (diatoms, krill,
and other organisms), which form the
base of the food chain in the Study
Area. Small coastal pelagic fishes
depend on this plankton and in turn are
fed on by larger species (such as highly
migratory species). The high fish
diversity found in the Study Area
occurs for several reasons: (1) The
ranges of many temperate and tropical
species extend into Southern California,
(2) the area has complex bottom features
and physical oceanographic features
that include several water masses and a
changeable marine climate offshore
(Allen et al. 2006; Horn and Allen
1978), and (3) the islands and coastal
areas provide a diversity of habitats that
include soft bottom, rocky reefs, kelp
beds, and estuaries, bays, and lagoons.
All fish have two sensory systems to
detect sound in the water: The inner ear,
which functions very much like the
inner ear in other vertebrates, and the
lateral line, which consists of a series of
receptors along the fish’s body (Popper
2008). The inner ear generally detects
relatively higher-frequency sounds,
while the lateral line detects water
motion at low frequencies (below a few
hundred Hz) (Hastings and Popper
2005). Although hearing capability data
only exist for fewer than 100 of the
32,000 fish species, current data suggest
that most species of fish detect sounds
from 50 to 1,000 Hz, with few fish
hearing sounds above 4 kHz (Popper
2008). It is believed that most fish have
their best hearing sensitivity from 100 to
400 Hz (Popper 2003). Additionally,
some clupeids (shad in the subfamily
Alosinae) possess ultrasonic hearing
(i.e., able to detect sounds above 100
kHz) (Astrup 1999). Permanent hearing
loss, or PTS, has not been documented
in fish. The sensory hair cells of the
inner ear in fish can regenerate after
they are damaged, unlike in mammals
where sensory hair cells loss is
permanent (Lombarte et al. 1993; Smith
et al. 2006). As a consequence, any
hearing loss in fish may be as temporary
as the timeframe required to repair or
replace the sensory cells that were
damaged or destroyed (Smith et al.
2006).
Potential direct injuries from acoustic
transmissions are unlikely because of
the relatively lower peak pressures and
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slower rise times than potentially
injurious sources such as explosives.
Acoustic sources also lack the strong
shock waves associated with an
explosion. Therefore, direct injury is not
likely to occur from exposure to sonar.
Only a few fish species are able to detect
high-frequency sonar and could have
behavioral reactions or experience
auditory masking during these
activities. These effects are expected to
be transient and long-term
consequences for the population are not
expected. Hearing specialists are not
expected to be within the Study Area.
If hearing specialists were present, they
would have to in close vicinity to the
source to experience effects from the
acoustic transmission. While a large
number of fish species may be able to
detect low-frequency sonar, some midfrequency sonar and other active
acoustic sources, low-frequency and
mid-frequency acoustic sources are not
planned as part of the proposed
activities. Overall effects to fish from
active sonar sources would be localized,
temporary and infrequent.
Based on the detailed review within
the Navy’s EA for 2015 Civilian Port
Defense training activities and the
discussion above, there would be no
effects to marine mammals resulting
from loss or modification of marine
mammal habitat or prey species related
to the proposed activities.
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Marine Mammal Avoidance
Marine mammals may be temporarily
displaced from areas where Navy
Civilian Port Defense training occurring,
but the area should be utilized again
after the activities have ceased.
Avoidance of an area can help the
animal avoid further acoustic effects by
avoiding or reducing further exposure.
The intermittent or short duration of
training activities should prevent
animals from being exposed to stressors
on a continuous basis. In areas of
repeated and frequent acoustic
disturbance, some animals may
habituate or learn to tolerate the new
baseline or fluctuations in noise level.
While some animals may not return to
an area, or may begin using an area
differently due to training and testing
activities, most animals are expected to
return to their usual locations and
behavior.
Effects of Habitat Impacts on Marine
Mammals
The proposed Civilian Port Defense
training activities are not expected to
have any habitat-related effects that
cause significant or long-term
consequences for individual marine
mammals, their populations, or prey
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species. Based on the discussions above,
there will be no loss or modification of
marine mammal habitat and as a result
no impacts to marine mammal
populations.
Proposed Mitigation
In order to issue an incidental take
authorization under section 101(a)(5)(A)
and (D) of the MMPA, NMFS must set
forth the ‘‘permissible methods of taking
pursuant to such activity, and other
means of effecting the least practicable
adverse impact on such species or stock
and its habitat, paying particular
attention to rookeries, mating grounds,
and areas of similar significance.’’
NMFS’ duty under this ‘‘least
practicable adverse impact’’ standard is
to prescribe mitigation reasonably
designed to minimize, to the extent
practicable, any adverse populationlevel impacts, as well as habitat
impacts. While population-level
impacts can be minimized by reducing
impacts on individual marine mammals,
not all takes translate to populationlevel impacts. NMFS’ primary objective
under the ‘‘least practicable adverse
impact’’ standard is to design mitigation
targeting those impacts on individual
marine mammals that are most likely to
lead to adverse population-level effects.
The NDAA of 2004 amended the
MMPA as it relates to military-readiness
activities and the ITA process such that
‘‘least practicable adverse impact’’ shall
include consideration of personnel
safety, practicality of implementation,
and impact on the effectiveness of the
‘‘military readiness activity.’’ The
training activities described in the
Navy’s application are considered
military readiness activities.
NMFS reviewed the proposed
activities and the proposed mitigation
measures as described in the application
to determine if they would result in the
least practicable adverse effect on
marine mammals, which includes a
careful balancing of the likely benefit of
any particular measure to the marine
mammals with the likely effect of that
measure on personnel safety,
practicality of implementation, and
impact on the effectiveness of the
‘‘military-readiness activity.’’ Included
below are the mitigation measures the
Navy proposed in their application.
NMFS worked with the Navy to develop
these proposed measures, and they are
informed by years of experience and
monitoring.
The Navy’s proposed mitigation
measures are modifications to the
proposed activities that are
implemented for the sole purpose of
reducing a specific potential
environmental impact on a particular
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resource. These do not include standard
operating procedures, which are
established for reasons other than
environmental benefit. Most of the
following proposed mitigation measures
are currently, or were previously,
implemented as a result of past
environmental compliance documents.
The Navy’s overall approach to
assessing potential mitigation measures
is based on two principles: (1)
Mitigation measures will be effective at
reducing potential impacts on the
resource, and (2) from a military
perspective, the mitigation measures are
practicable, executable, and safety and
readiness will not be impacted.
The mitigation measures applicable to
the proposed Civilian Port Defense
training activities are the same as those
identified in the Mariana Islands
Training and Testing Environmental
Impact Statement/Overseas
Environmental Impact Statement (MITT
EIS/OEIS), Chapter 5. All mitigation
measures which could be applicable to
the proposed activities are provided
below. For the mitigation measures
described below, the Lookout
Procedures and Mitigation Zone
Procedure sections from the MITT EIS/
OEIS have been combined. For details
regarding the methodology for analyzing
each measure, see the MITT EIS/OEIS,
Chapter 5.
Lookout Procedure Measures
The Navy will have two types of
lookouts for the purposes of conducting
visual observations: (1) Those
positioned on surface ships, and (2)
those positioned in aircraft or on boats.
Lookouts positioned on surface ships
will be dedicated solely to diligent
observation of the air and surface of the
water. They will have multiple
observation objectives, which include
but are not limited to detecting the
presence of biological resources and
recreational or fishing boats, observing
mitigation zones, and monitoring for
vessel and personnel safety concerns.
Lookouts positioned on surface ships
will typically be personnel already
standing watch or existing members of
the bridge watch team who become
temporarily relieved of job
responsibilities that would divert their
attention from observing the air or
surface of the water (such as navigation
of a vessel).
Due to aircraft and boat manning and
space restrictions, Lookouts positioned
in aircraft or on boats will consist of the
aircraft crew, pilot, or boat crew.
Lookouts positioned in aircraft and
boats may necessarily be responsible for
tasks in addition to observing the air or
surface of the water (for example,
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navigation of a helicopter or rigid hull
inflatable boat). However, aircraft and
boat lookouts will, to the maximum
extent practicable and consistent with
aircraft and boat safety and training
requirements, comply with the
observation objectives described above
for Lookouts positioned on surface
ships.
Mitigation Measures
High-Frequency Active Sonar
The Navy will have one Lookout on
ships or aircraft conducting highfrequency active sonar activities
associated with mine warfare activities
at sea.
Mitigation will include visual
observation from a vessel or aircraft
(with the exception of platforms
operating at high altitudes) immediately
before and during active transmission
within a mitigation zone of 200 yards
(yds. [183 m]) from the active sonar
source. If the source can be turned off
during the activity, active transmission
will cease if a marine mammal is
sighted within the mitigation zone.
Active transmission will recommence if
any one of the following conditions is
met: (1) The animal is observed exiting
the mitigation zone, (2) the animal is
thought to have exited the mitigation
zone based on a determination of its
course and speed and the relative
motion between the animal and the
source, (3) the mitigation zone has been
clear from any additional sightings for a
period of 10 minutes for an aircraftdeployed source, (4) the mitigation zone
has been clear from any additional
sightings for a period of 30 minutes for
a vessel-deployed source, (5) the vessel
or aircraft has repositioned itself more
than 400 yds (366 m) away from the
location of the last sighting, or (6) the
vessel concludes that dolphins are
deliberately closing in to ride the
vessel’s bow wave (and there are no
other marine mammal sightings within
the mitigation zone).
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Physical Disturbance and Strike
Although the Navy does not
anticipate that any marine mammals
would be struck during the conduct of
Civilian Port Defense training activities,
the mitigation measures below will be
implemented and adhered to.
Vessels—While underway, vessels
will have a minimum of one Lookout.
Vessels will avoid approaching marine
mammals head on and will maneuver to
maintain a mitigation zone of 500 yds
(457 m) around observed whales, and
200 yds (183 m) around all other marine
mammals (except bow riding dolphins),
providing it is safe to do so.
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Towed In-Water Devices—The Navy
will have one Lookout during activities
using towed in-water devices when
towed from a manned platform.
The Navy will ensure that towed inwater devices being towed from manned
platforms avoid coming within a
mitigation zone of 250 yds (229 m)
around any observed marine mammal,
providing it is safe to do so.
Mitigation Conclusions
NMFS has carefully evaluated the
Navy’s proposed mitigation measures—
many of which were developed with
NMFS’ input during previous Navy
Training and Testing authorizations—
and considered a range of other
measures in the context of ensuring that
NMFS prescribes the means of effecting
the least practicable adverse impact on
the affected marine mammal species
and stocks and their habitat. Our
evaluation of potential measures
included consideration of the following
factors in relation to one another: The
manner in which, and the degree to
which, the successful implementation of
the mitigation measures is expected to
reduce the likelihood and/or magnitude
of adverse impacts to marine mammal
species and stocks and their habitat; the
proven or likely efficacy of the
measures; and the practicability of the
suite of measures for applicant
implementation, including
consideration of personnel safety,
practicality of implementation, and
impact on the effectiveness of the
military readiness activity.
Any mitigation measure(s) prescribed
by NMFS should be able to accomplish,
have a reasonable likelihood of
accomplishing (based on current
science), or contribute to accomplishing
one or more of the general goals listed
below:
a. Avoid or minimize injury or death
of marine mammals wherever possible
(goals b, c, and d may contribute to this
goal).
b. Reduce the number of marine
mammals (total number or number at
biologically important time or location)
exposed to received levels of MFAS/
HFAS, underwater detonations, or other
activities expected to result in the take
of marine mammals (this goal may
contribute to a, above, or to reducing
harassment takes only).
c. Reduce the number of times (total
number or number at biologically
important time or location) individuals
would be exposed to received levels of
MFAS/HFAS, underwater detonations,
or other activities expected to result in
the take of marine mammals (this goal
may contribute to a, above, or to
reducing harassment takes only).
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d. Reduce the intensity of exposures
(either total number or number at
biologically important time or location)
to received levels of MFAS/HFAS,
underwater detonations, or other
activities expected to result in the take
of marine mammals (this goal may
contribute to a, above, or to reducing the
severity of harassment takes only).
e. Avoid or minimize adverse effects
to marine mammal habitat, paying
special attention to the food base,
activities that block or limit passage to
or from biologically important areas,
permanent destruction of habitat, or
temporary destruction/disturbance of
habitat during a biologically important
time.
f. For monitoring directly related to
mitigation—increase the probability of
detecting marine mammals, thus
allowing for more effective
implementation of the mitigation (shutdown zone, etc.).
Based on our evaluation of the Navy’s
proposed measures, as well as other
measures considered by NMFS, NMFS
has determined preliminarily that the
Navy’s proposed mitigation measures
are adequate means of effecting the least
practicable adverse impacts on marine
mammals species or stocks and their
habitat, paying particular attention to
rookeries, mating grounds, and areas of
similar significance, while also
considering personnel safety,
practicality of implementation, and
impact on the effectiveness of the
military readiness activity.
The proposed IHA comment period
provides the public an opportunity to
submit recommendations, views, and/or
concerns regarding this action and the
proposed mitigation measures. While
NMFS has determined preliminarily
that the Navy’s proposed mitigation
measures would effect the least
practicable adverse impact on the
affected species or stocks and their
habitat, NMFS will consider all public
comments to help inform our final
decision. Consequently, the proposed
mitigation measures may be refined,
modified, removed, or added to prior to
the issuance of the authorization based
on public comments received, and
where appropriate, further analysis of
any additional mitigation measures.
Proposed Monitoring and Reporting
Section 101(a)(5)(A) of the MMPA
states that in order to issue an ITA for
an activity, NMFS must set forth
‘‘requirements pertaining to the
monitoring and reporting of such
taking.’’ The MMPA implementing
regulations at 50 CFR 216.104 (a)(13)
indicate that requests for LOAs must
include the suggested means of
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accomplishing the necessary monitoring
and reporting that will result in
increased knowledge of the species and
of the level of taking or impacts on
populations of marine mammals that are
expected to be present.
Integrated Comprehensive Monitoring
Program
The U.S. Navy has coordinated with
NMFS to develop an overarching
program plan in which specific
monitoring would occur. This plan is
called the Integrated Comprehensive
Monitoring Program (ICMP) (U.S.
Department of the Navy, 2011). The
ICMP has been developed in direct
response to Navy permitting
requirements established in various
MMPA Final Rules, Endangered Species
Act consultations, Biological Opinions,
and applicable regulations. As a
framework document, the ICMP applies
by regulation to those activities on
ranges and operating areas for which the
Navy is seeking or has sought incidental
take authorizations. The ICMP is
intended to coordinate monitoring
efforts across all regions and to allocate
the most appropriate level and type of
effort based on set of standardized
research goals, and in acknowledgement
of regional scientific value and resource
availability.
The ICMP is designed to be a flexible,
scalable, and adjustable plan. The ICMP
is evaluated annually through the
adaptive management process to assess
progress, provide a matrix of goals for
the following year, and make
recommendations for refinement. Future
monitoring will address the following
ICMP top-level goals through a series of
regional and ocean basin study
questions with a priority study and
funding focus on species of interest as
identified for each range complex.
• An increase in our understanding of
the likely occurrence of marine
mammals and/or ESA-listed marine
species in the vicinity of the action (i.e.,
presence, abundance, distribution, and/
or density of species);
• An increase in our understanding of
the nature, scope, or context of the
likely exposure of marine mammals
and/or ESA-listed species to any of the
potential stressor(s) associated with the
action (e.g., tonal and impulsive sound),
through better understanding of one or
more of the following: (1) The action
and the environment in which it occurs
(e.g., sound source characterization,
propagation, and ambient noise levels);
(2) the affected species (e.g., life history
or dive patterns); (3) the likely cooccurrence of marine mammals and/or
ESA-listed marine species with the
action (in whole or part) associated with
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specific adverse effects, and/or; (4) the
likely biological or behavioral context of
exposure to the stressor for the marine
mammal and/or ESA-listed marine
species (e.g., age class of exposed
animals or known pupping, calving or
feeding areas);
• An increase in our understanding of
how individual marine mammals or
ESA-listed marine species respond
(behaviorally or physiologically) to the
specific stressors associated with the
action (in specific contexts, where
possible, e.g., at what distance or
received level);
• An increase in our understanding of
how anticipated individual responses,
to individual stressors or anticipated
combinations of stressors, may impact
either: (1) The long-term fitness and
survival of an individual; or (2) the
population, species, or stock (e.g.,
through effects on annual rates of
recruitment or survival);
• An increase in our understanding of
the effectiveness of mitigation and
monitoring measures;
• A better understanding and record
of the manner in which the authorized
entity complies with the ITA and
Incidental Take Statement;
• An increase in the probability of
detecting marine mammals (through
improved technology or methods), both
specifically within the safety zone (thus
allowing for more effective
implementation of the mitigation) and
in general, to better achieve the above
goals; and
• A reduction in the adverse impact
of activities to the least practicable
level, as defined in the MMPA.
The ICMP will also address relative
investments to different range
complexes based on goals across all
range complexes, and monitoring will
leverage multiple techniques for data
acquisition and analysis whenever
possible. Because the ICMP does not
specify actual monitoring field work or
projects in a given area, it allows the
Navy to coordinate its monitoring to
gather the best scientific data possible
across all areas in which the Navy
operates. Details of the ICMP are
available online (http://www.navy
marinespeciesmonitoring.us/).
Strategic Planning Process for Marine
Species Monitoring
The Navy also developed the Strategic
Planning Process for Marine Species
Monitoring, which establishes the
guidelines and processes necessary to
develop, evaluate, and fund individual
projects based on objective scientific
study questions. The process uses an
underlying framework designed around
top-level goals, a conceptual framework
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incorporating a progression of
knowledge, and in consultation with a
Scientific Advisory Group and other
regional experts. The Strategic Planning
Process for Marine Species Monitoring
would be used to set intermediate
scientific objectives, identify potential
species of interest at a regional scale,
and evaluate and select specific
monitoring projects to fund or continue
supporting for a given fiscal year. This
process would also address relative
investments to different range
complexes based on goals across all
range complexes, and monitoring would
leverage multiple techniques for data
acquisition and analysis whenever
possible. The Strategic Planning Process
for Marine Species Monitoring is also
available online (http://www.navy
marinespeciesmonitoring.us/).
Reporting
In order to issue an incidental take
authorization for an activity, section
101(a)(5)(A) and (D) of the MMPA states
that NMFS must set forth ‘‘requirements
pertaining to the monitoring and
reporting of such taking.’’ Effective
reporting is critical both to compliance
as well as ensuring that the most value
is obtained from the required
monitoring. Some of the reporting
requirements are still in development
and the final authorization may contain
additional details not contained here.
Additionally, proposed reporting
requirements may be modified,
removed, or added based on information
or comments received during the public
comment period. Reports from
individual monitoring events, results of
analyses, publications, and periodic
progress reports for specific monitoring
projects would be posted to the Navy’s
Marine Species Monitoring Web
portal: http://
www.navymarinespeciesmonitoring.us.
General Notification of Injured or
Dead Marine Mammals—If any injury or
death of a marine mammal is observed
during the Civilian Port Defense training
activities, the Navy will immediately
halt the activity and report the incident
to NMFS following the standard
monitoring and reporting measures
consistent with the MITT EIS/OEIS. The
reporting measures include the
following procedures:
Navy personnel shall ensure that
NMFS (regional stranding coordinator)
is notified immediately (or as soon as
clearance procedures allow) if an
injured or dead marine mammal is
found during or shortly after, and in the
vicinity of, any Navy training activity
utilizing high-frequency active sonar.
The Navy shall provide NMFS with
species or description of the animal(s),
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the condition of the animal(s) (including
carcass condition if the animal is dead),
location, time of first discovery,
observed behaviors (if alive), and photo
or video (if available). The Navy shall
consult the Stranding Response and
Communication Plan to obtain more
specific reporting requirements for
specific circumstances.
Vessel Strike—Vessel strike during
Navy Civilian Port Defense activities in
the Study Area is not anticipated;
however, in the event that a Navy vessel
strikes a whale, the Navy shall do the
following:
Immediately report to NMFS
(pursuant to the established
Communication Protocol) the:
• Species identification (if known);
• Location (latitude/longitude) of the
animal (or location of the strike if the
animal has disappeared);
• Whether the animal is alive or dead
(or unknown); and
• The time of the strike.
As soon as feasible, the Navy shall
report to or provide to NMFS, the:
• Size, length, and description
(critical if species is not known) of
animal;
• An estimate of the injury status
(e.g., dead, injured but alive, injured
and moving, blood or tissue observed in
the water, status unknown, disappeared,
etc.);
• Description of the behavior of the
whale during event, immediately after
the strike, and following the strike (until
the report is made or the animal is no
longer sighted);
• Vessel class/type and operational
status;
• Vessel length;
• Vessel speed and heading; and
• To the best extent possible, obtain
a photo or video of the struck animal,
if the animal is still in view.
Within 2 weeks of the strike, provide
NMFS:
• A detailed description of the
specific actions of the vessel in the 30minute timeframe immediately
preceding the strike, during the event,
and immediately after the strike (e.g.,
the speed and changes in speed, the
direction and changes in direction,
other maneuvers, sonar use, etc., if not
classified);
• A narrative description of marine
mammal sightings during the event and
immediately after, and any information
as to sightings prior to the strike, if
available; and use established Navy
shipboard procedures to make a camera
available to attempt to capture
photographs following a ship strike.
NMFS and the Navy will coordinate
to determine the services the Navy may
provide to assist NMFS with the
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investigation of the strike. The response
and support activities to be provided by
the Navy are dependent on resource
availability, must be consistent with
military security, and must be
logistically feasible without
compromising Navy personnel safety.
Assistance requested and provided may
vary based on distance of strike from
shore, the nature of the vessel that hit
the whale, available nearby Navy
resources, operational and installation
commitments, or other factors.
Estimated Take by Incidental
Harassment
In the Potential Effects section,
NMFS’ analysis identified the lethal
responses, physical trauma, sensory
impairment (PTS, TTS, and acoustic
masking), physiological responses
(particular stress responses), and
behavioral responses that could
potentially result from exposure to
active sonar (MFAS/HFAS). In this
section, the potential effects to marine
mammals from active sonar will be
related to the MMPA regulatory
definitions of Level A and Level B
harassment and attempt to quantify the
effects that might occur from the
proposed activities in the Study Area.
As mentioned previously, behavioral
responses are context-dependent,
complex, and influenced to varying
degrees by a number of factors other
than just received level. For example, an
animal may respond differently to a
sound emanating from a ship that is
moving towards the animal than it
would to an identical received level
coming from a vessel that is moving
away, or to a ship traveling at a different
speed or at a different distance from the
animal. At greater distances, though, the
nature of vessel movements could also
potentially not have any effect on the
animal’s response to the sound. In any
case, a full description of the suite of
factors that elicited a behavioral
response would require a mention of the
vicinity, speed and movement of the
vessel, or other factors. So, while sound
sources and the received levels are the
primary focus of the analysis and those
that are laid out quantitatively in the
regulatory text, it is with the
understanding that other factors related
to the training are sometimes
contributing to the behavioral responses
of marine mammals, although they
cannot be quantified.
Definition of Harassment
As mentioned previously, with
respect to military readiness activities,
section 3(18)(B) of the MMPA defines
‘‘harassment’’ as: ‘‘(i) any act that
injures or has the significant potential to
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injure a marine mammal or marine
mammal stock in the wild [Level A
Harassment]; or (ii) any act that disturbs
or is likely to disturb a marine mammal
or marine mammal stock in the wild by
causing disruption of natural behavioral
patterns, including, but not limited to,
migration, surfacing, nursing, breeding,
feeding, or sheltering, to a point where
such behavioral patterns are abandoned
or significantly altered [Level B
Harassment].’’ It is important to note
that, as Level B harassment is
interpreted here and quantified by the
behavioral thresholds described below,
the fact that a single behavioral pattern
(of unspecified duration) is abandoned
or significantly altered and classified as
a Level B take does not mean,
necessarily, that the fitness of the
harassed individual is affected either at
all or significantly, or that, for example,
a preferred habitat area is abandoned.
Further analysis of context and duration
of likely exposures and effects is
necessary to determine the impacts of
the estimated effects on individuals and
how those may translate to population
level impacts, and is included in the
Analysis and Negligible Impact
Determination.
Level B Harassment
Of the potential effects that were
described earlier in this document, the
following are the types of effects that
fall into the Level B harassment
category:
Behavioral Harassment—Behavioral
disturbance that rises to the level
described in the definition above, when
resulting from exposures to nonimpulsive or impulsive sound, is
considered Level B harassment. Some of
the lower level physiological stress
responses discussed earlier would also
likely co-occur with the predicted
harassments, although these responses
are more difficult to detect and fewer
data exist relating these responses to
specific received levels of sound. When
Level B harassment is predicted based
on estimated behavioral responses,
those takes may have a stress-related
physiological component as well.
As the statutory definition is currently
applied, a wide range of behavioral
reactions may qualify as Level B
harassment under the MMPA, including
but not limited to avoidance of the
sound source, temporary changes in
vocalizations or dive patters, temporary
avoidance of an area, or temporary
disruption of feeding, migrating, or
reproductive behaviors. The estimates
calculated by the Navy using the
acoustic thresholds do not differentiate
between the different types of potential
behavioral reactions. Nor do the
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estimates provide information regarding
the potential fitness or other biological
consequences of the reactions on the
affected individuals. We therefore
consider the available scientific
evidence to determine the likely nature
of the modeled behavioral responses
and the potential fitness consequences
for affected individuals.
Temporary Threshold Shift (TTS)—As
discussed previously, TTS can affect
how an animal behaves in response to
the environment, including
conspecifics, predators, and prey. The
following physiological mechanisms are
thought to play a role in inducing
auditory fatigue: Effects to sensory hair
cells in the inner ear that reduce their
sensitivity, modification of the chemical
environment within the sensory cells;
residual muscular activity in the middle
ear, displacement of certain inner ear
membranes; increased blood flow; and
post-stimulatory reduction in both
efferent and sensory neural output.
Ward (1997) suggested that when these
effects result in TTS rather than PTS,
they are within the normal bounds of
physiological variability and tolerance
and do not represent a physical injury.
Additionally, Southall et al. (2007)
indicate that although PTS is a tissue
injury, TTS is not because the reduced
hearing sensitivity following exposure
to intense sound results primarily from
fatigue, not loss, of cochlear hair cells
and supporting structures and is
reversible. Accordingly, NMFS classifies
TTS (when resulting from exposure to
sonar and other active acoustic sources
and explosives and other impulsive
sources) as Level B harassment, not
Level A harassment (injury).
Level A Harassment
Of the potential effects that were
described earlier, the types of effects
that can fall into the Level A harassment
category (unless they further rise to the
level of serious injury or mortality)
include permanent threshold shift
(PTS), tissue damage due to acoustically
mediated bubble growth, tissue damage
due to behaviorally mediated bubble
growth, physical disruption of tissues
resulting from explosive shock wave,
and vessel strike and other physical
disturbance (strike from towed in-water
devices). Level A harassment and
mortality are not anticipated to result
from any of the proposed Civilian Port
Defense activities; therefore, these
effects will not be discussed further.
Although the Navy does not anticipate
that any marine mammals would be
struck during proposed Civilian Port
Defense activities, the mitigation
measures described above in Proposed
Mitigation will be implemented and
adhered to.
Criteria and Thresholds for Predicting
Acoustic Impacts
Criteria and thresholds used for
determining the potential effects from
the Civilian Port Defense activities are
consistent with those used in the Navy’s
Phase II Training and Testing EISs (e.g.,
HSTT, MITT). Table 3 below provides
the criteria and thresholds used in this
analysis for estimating quantitative
acoustic exposures of marine mammals
from the proposed training activities.
Weighting criteria are shown in the
table below. Southall et al. (2007)
proposed frequency-weighting to
account for the frequency bandwidth of
hearing in marine mammals. Frequencyweighting functions are used to adjust
the received sound level based on the
sensitivity of the animal to the
frequency of the sound. Details
regarding these criteria and thresholds
can be found in Finneran and Jenkins
(2012).
TABLE 3—INJURY (PTS) AND DISTURBANCE (TTS, BEHAVIORAL) THRESHOLDS FOR UNDERWATER SOUNDS
Physiological criteria
Group
Species
Behavioral criteria
Onset TTS
220 dB SEL (Type
I weighted).
Mysticete Dose
weighted).
Mid-Frequency
Cetaceans.
High-Frequency
Cetaceans.
Harbor Porpoises ...
Most delphinids, beaked whales, medium and large toothed whales.
Porpoises,
River
dolphins,
Cephalorynchus spp., Kogia sp.
Harbor porpoises .................................
Odontocete Dose Function (Type I
weighted).
Odontocete Dose Function (Type I
weighted).
120 dB SPL, unweighted ....................
Beaked Whales ......
All Ziphiidae .........................................
140 dB SPL, unweighted ....................
Phocidae (in water)
Harbor, Bearded, Hooded, Common,
Spotted, Ringed, Baikal, Caspian,
Harp, Ribbon, Gray seals, Monk,
Elephant, Ross, Crabeater, Leopard, and Weddell seals.
Guadalupe fur seal, Northern fur seal,
California sea lion, Steller sea lion.
Odontocete Dose Function (Type I
weighted).
178 dB Sound Exposure Level
(SEL) 1 (Type II
weighted).
178 dB SEL (Type
II weighted).
152 dB SEL (Type
II weighted).
152 dB SEL (Type
II weighted).
178 dB SEL (Type
II weighted).
183 dB SEL (Type
I weighted).
Odontocete Dose Function (Type I
weighted).
206 dB SEL (Type
I weighted).
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equivalent context, the severity of a
marine mammal behavioral response is
also expected to increase with received
level (Houser and Moore, 2014). NMFS
will continue to modify these criteria as
new data become available and can be
appropriately and effectively
incorporated.
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I
198 dB SEL (Type
II weighted).
172 dB SEL (Type
II weighted).
172 dB SEL (Type
II weighted).
198 dB SEL (Type
II weighted).
197 dB SEL (Type
I weighted).
All mysticetes ......................................
As discussed earlier, factors other
than received level (such as distance
from or bearing to the sound source,
context of animal at time of exposure)
can affect the way that marine mammals
respond; however, data to support a
quantitative analysis of those (and other
factors) do not currently exist. It is also
worth specifically noting that while
context is very important in marine
mammal response, given otherwise
(Type
198 dB SEL (Type
II weighted).
Low-Frequency
Cetaceans.
Otariidae (in water)
Function
Onset PTS
Marine Mammal Density Estimates
A quantitative analysis of impacts on
a species requires data on the
abundance and distribution of the
species population in the potentially
impacted area. The most appropriate
unit of metric for this type of analysis
is density, which is described as the
number of animals present per unit area.
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There is no single source of density
data for every area, species, and season
because of the fiscal costs, resources,
and effort involved in NMFS providing
enough survey coverage to sufficiently
estimate density. Therefore, to
characterize the marine species density
for large areas such as the Study Area,
the Navy needed to compile data from
multiple sources. Each data source may
use different methods to estimate
density, of which, uncertainty in the
estimate can be directly related to the
method applied. To develop a database
of marine species density estimates, the
Navy, in consultation with NMFS
experts, adopted a protocol to select the
best available data sources (including
habitat-based density models, linetransect analyses, and peer-reviewed
published studies) based on species,
area, and season (see the Navy’s Pacific
Marine Species Density Database
Technical Report; U.S. Department of
the Navy, 2012, 2014). The resulting
Geographic Information System (GIS)
database includes one single spatial and
seasonal density value for every marine
mammal present within the Study Area.
The Navy Marine Species Density
Database includes a compilation of the
best available density data from several
primary sources and published works
including survey data from NMFS
within the U.S. EEZ. NMFS is the
primary agency responsible for
estimating marine mammal and sea
turtle density within the U.S. EEZ.
NMFS publishes annual SARs for
various regions of U.S. waters and
covers all stocks of marine mammals
within those waters. The majority of
species that occur in the Study Area are
covered by the Pacific Region Stock
Assessment Report (Carretta et al.,
2014). Other independent researchers
often publish density data or research
covering a particular marine mammal
species, which is integrated into the
NMFS SARs.
For most cetacean species, abundance
is estimated using line-transect methods
that employ a standard equation to
derive densities based on sighting data
collected from systematic ship or aerial
surveys. More recently, habitat-based
density models have been used
effectively to model cetacean density as
a function of environmental variables
(e.g., Redfern et al., 2006; Barlow et al.,
2009; Becker et al., 2010; Becker et al.,
2012a; Becker et al., 2012b; Becker,
2012c; Forney et al., 2012). Where the
data supports habitat based density
modeling, the Navy’s database uses
those density predictions. Habitat-based
density models allow predictions of
cetacean densities on a finer spatial
scale than traditional line-transect
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analyses because cetacean densities are
estimated as a continuous function of
habitat variables (e.g., sea surface
temperature, water depth). Within most
of the world’s oceans, however there
have not been enough systematic
surveys to allow for line-transect
density estimation or the development
of habitat models. To get an
approximation of the cetacean species
distribution and abundance for
unsurveyed areas, in some cases it is
appropriate to extrapolate data from
areas with similar oceanic conditions
where extensive survey data exist.
Habitat Suitability Indexes or Relative
Environmental Suitability have also
been used in data-limited areas to
estimate occurrence based on existing
observations about a given species’
presence and relationships between
basic environmental conditions
(Kaschner et al., 2006).
Methods used to estimate pinniped atsea density are generally quite different
than those described above for
cetaceans. Pinniped abundance is
generally estimated via shore counts of
animals at known rookeries and haulout
sites. For example, for species such as
the California sea lion, population
estimates are based on counts of pups at
the breeding sites (Carretta et al., 2014).
However, this method is not appropriate
for other species such as harbor seals,
whose pups enter the water shortly after
birth. Population estimates for these
species are typically made by counting
the number of seals ashore and applying
correction factors based on the
proportion of animals estimated to be in
the water (Carretta et al., 2014).
Population estimates for pinniped
species that occur in the Study Area are
provided in the Pacific Region Stock
Assessment Report (Carretta et al.,
2014). Translating these population
estimates to in-water densities presents
challenges because the percentage of
seals or sea lions at sea compared to
those on shore is species-specific and
depends on gender, age class, time of
year (molt and breeding/pupping
seasons), foraging range, and for species
such as harbor seal, time of day and tide
level. These parameters were identified
from the literature and used to establish
correction factors which were then
applied to estimate the proportion of
pinnipeds that would be at sea within
the Study Area for a given season.
Density estimates for each species in
the Study Area, and the sources for
these estimates, are provided in Chapter
4 of the application and in the Navy’s
Pacific Marine Species Density Database
Technical Report.
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Quantitative Modeling To Estimate Take
The Navy performed a quantitative
analysis to estimate the number of
mammals that could be exposed to the
acoustic transmissions during the
proposed Civilian Port Defense
activities. Inputs to the quantitative
analysis included marine mammal
density estimates, marine mammal
depth occurrence distributions
(Watwood and Buonantony 2012),
oceanographic and environmental data,
marine mammal hearing data, and
criteria and thresholds for levels of
potential effects. The quantitative
analysis consists of computer modeled
estimates and a post-model analysis to
determine the number of potential
mortalities and harassments. The model
calculates sound energy propagation
from the proposed sonars, the sound
received by animat (virtual animal)
dosimeters representing marine
mammals distributed in the area around
the modeled activity, and whether the
sound received by a marine mammal
exceeds the thresholds for effects. The
model estimates are then further
analyzed to consider animal avoidance
and implementation of mitigation
measures, resulting in final estimates of
effects due to the proposed training
activities.
The Navy developed a set of software
tools and compiled data for estimating
acoustic effects on marine mammals
without consideration of behavioral
avoidance or Navy’s standard
mitigations. These databases and tools
collectively form the Navy Acoustic
Effects Model (NAEMO). In NAEMO,
animats (virtual animals) are distributed
non-uniformly based on species-specific
density, depth distribution, and group
size information. Animats record energy
received at their location in the water
column. A fully three-dimensional
environment is used for calculating
sound propagation and animat exposure
in NAEMO. Site-specific bathymetry,
sound speed profiles, wind speed, and
bottom properties are incorporated into
the propagation modeling process.
NAEMO calculates the likely
propagation for various levels of energy
(sound or pressure) resulting from each
source used during the training event.
NAEMO then records the energy
received by each animat within the
energy footprint of the event and
calculates the number of animats having
received levels of energy exposures that
fall within defined impact thresholds.
Predicted effects on the animats within
a scenario are then tallied and the
highest order effect (based on severity of
criteria; e.g., PTS over TTS) predicted
for a given animat is assumed. Each
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scenario or each 24-hour period for
scenarios lasting greater than 24 hours
is independent of all others, and
therefore, the same individual marine
animal could be impacted during each
independent scenario or 24-hour period.
In few instances, although the activities
themselves all occur within the Study
Area, sound may propagate beyond the
boundary of the Study Area. Any
exposures occurring outside the
boundary of the Study Area are counted
as if they occurred within the Study
Area boundary. NAEMO provides the
initial estimated impacts on marine
species with a static horizontal
distribution. These model-estimated
results are then further analyzed to
account for pre-activity avoidance by
sensitive species, mitigation
(considering sound source and
platform), and avoidance of repeated
sound exposures by marine mammals,
producing the final predictions of
effects used in this request for an IHA.
There are limitations to the data used
in the acoustic effects model, and the
results must be interpreted within these
context. While the most accurate data
and input assumptions have been used
in the modeling, when there is a lack of
definitive data to support an aspect of
the modeling, modeling assumptions
believed to overestimate the number of
exposures have been chosen:
• Animats are modeled as being
underwater, stationary, and facing the
source and therefore always predicted to
receive the maximum sound level (i.e.,
no porpoising or pinnipeds’ heads
above water). Some odontocetes have
been shown to have directional hearing,
with best hearing sensitivity facing a
sound source and higher hearing
thresholds for sounds propagating
towards the rear or side of an animal
(Kastelein et al. 2005; Mooney et al.
2008; Popov and Supin 2009).
• Animats do not move horizontally
(but change their position vertically
within the water column), which may
overestimate physiological effects such
as hearing loss, especially for slow
moving or stationary sound sources in
the model.
• Animats are stationary horizontally
and therefore do not avoid the sound
source, unlike in the wild where
animals would most often avoid
exposures at higher sound levels,
especially those exposures that may
result in PTS.
• Multiple exposures within any 24hour period are considered one
continuous exposure for the purposes of
calculating the temporary or permanent
hearing loss, because there are not
sufficient data to estimate a hearing
recovery function for the time between
exposures.
• Mitigation measures that are
implemented were not considered in the
model. In reality, sound-producing
activities would be reduced, stopped, or
delayed if marine mammals are detected
within the mitigation zones around
sound sources.
Because of these inherent model
limitations and simplifications, modelestimated results must be further
analyzed, considering such factors as
the range to specific effects, avoidance,
and the likelihood of successfully
implementing mitigation measures, in
order to determine the final estimate of
potential takes.
Impacts on Marine Mammals
Range to Effects—Table 4 provides
range to effects for active acoustic
sources to specific criteria determined
using NAEMO. Marine mammals within
these ranges would be predicted to
receive the associated effect. Range to
effects is important information in not
only predicting acoustic impacts, but
also in verifying the accuracy of model
results against real-world situations and
determining adequate mitigation ranges
to avoid higher level effects, especially
physiological effects to marine
mammals. Therefore, the ranges in
Table 4 provide realistic maximum
distances over which the specific effects
from the use of the AN/SQQ–32 high
frequency sonar, the only acoustic
source to be used in the proposed
activities that requires quantitative
analysis, would be possible.
TABLE 4—MAXIMUM RANGE TO TEMPORARY THRESHOLD SHIFT AND BEHAVIORAL EFFECTS FROM THE AN/SQQ–32 IN
THE LOS ANGELES/LONG BEACH STUDY AREA
Range to effects cold season
(m)
Hearing group
Behavioral
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Low Frequency Cetacean ................................................................................
Mid-Frequency Cetacean ................................................................................
High Frequency Cetacean ...............................................................................
Phocidae water ................................................................................................
Otariidae Odobenidae water ............................................................................
Avoidance Behavior and Mitigation
Measures—When sonar is active,
exposure to increased sound pressure
levels would likely involve individuals
that are moving through the area during
foraging trips. Pinnipeds may also be
exposed enroute to haul-out sites. As
discussed further in Chapter 7 of the
application and in Analysis and
Negligible Impact Determination below,
if exposure were to occur, both
pinnipeds and cetaceans could exhibit
behavioral changes such as increased
swimming speeds, increased surfacing
time, or decreased foraging. Most likely,
individuals affected by elevated
underwater noise would move away
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2,800
3,550
3,550
3,450
3,350
from the sound source and be
temporarily displaced from the
proposed Study Area. Any effects
experienced by individual marine
mammals are anticipated to be limited
to short-term disturbance of normal
behavior, temporary displacement or
disruption of animals which may occur
near the proposed training activities.
Therefore, the exposures requested are
expected to have no more than a minor
effect on individual animals and no
adverse effect on the populations of
these species.
Results from the quantitative analysis
should be regarded as conservative
estimates that are strongly influenced by
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TTS
Range to effects warm season
(m)
Behavioral
<50
<50
95
<50
<50
1,900
2,550
2,550
2,500
2,200
TTS
<50
<50
195
<50
<50
limited marine mammal population
data. While the numbers generated from
the quantitative analysis provide
conservative overestimates of marine
mammal exposures, the short duration,
limited geographic extent of Civilian
Port Defense training activities, and
mitigation measures would further limit
actual exposures.
Incidental Take Request
The Navy’s Draft EA for 2015 West
Coast Civilian Port Defense training
activities analyzed the following
stressors for potential impacts to marine
mammals:
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• Acoustic (sonar sources, vessel noise,
aircraft noise)
• Energy (electromagnetic devices and
lasers)
• Physical disturbance and strikes
(vessels, in-water devices, seafloor
objects)
NMFS and the Navy determined the
only stressor that could potentially
result in the incidental taking of marine
mammals per the definition of MMPA
harassment from the Civilian Port
Defense activities within the Study Area
is from acoustic transmissions related to
high-frequency sonar.
The methods of incidental take
associated with the acoustic
transmissions from the proposed
Civilian Port Defense are described
within Chapter 2 of the application.
Acoustic transmissions have the
potential to temporarily disturb or
displace marine mammals. Specifically,
only underwater active transmissions
may result in the ‘‘take’’ in the form of
Level B harassment.
Level A harassment and mortality are
not anticipated to result from any of the
proposed Civilian Port Defense
activities. Furthermore, Navy mitigation
and monitoring measures will be
implemented to further minimize the
potential for Level B takes of marine
mammals.
A detailed analysis of effects due to
marine mammal exposures to nonimpulsive sources (i.e., active sonar) in
the Study Area is presented in Chapter
6 of the application and in the
Estimated Take by Incidental
Harassment section of this proposed
IHA. Based on the quantitative acoustic
modeling and analysis described in
Chapter 6 of the application, Table 5
summarizes the Navy’s final take
request the Civilian Port Defense
training activities from October through
November 2015.
TABLE 5—TOTAL NUMBER OF EXPOSURES MODELED AND REQUESTED PER SPECIES FOR CIVILIAN PORT DEFENSE
TRAINING ACTIVITIES
Level B takes
requested
Percentage of
stock taken
(%)
Long-beaked common dolphin ................................................................................................................................
Short-beaked common dolphin ................................................................................................................................
Risso’s dolphin .........................................................................................................................................................
Pacific white-sided dolphin ......................................................................................................................................
Bottlenose dolphin coastal .......................................................................................................................................
Harbor seal ..............................................................................................................................................................
California sea lion ....................................................................................................................................................
8
727
21
40
48
8
46
0.007
0.177
0.330
0.149
14.985
0.026
0.015
Total ..................................................................................................................................................................
898
........................
Common name
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Analysis and Negligible Impact
Determination
Negligible impact is ‘‘an impact
resulting from the specified activity that
cannot be reasonably expected to, and is
not reasonably likely to, adversely affect
the species or stock through effects on
annual rates of recruitment or survival’’
(50 CFR 216.103). A negligible impact
finding is based on the lack of likely
adverse effects on annual rates of
recruitment or survival (i.e., populationlevel effects). An estimate of the number
of takes, alone, is not enough
information on which to base an impact
determination, as the severity of
harassment may vary greatly depending
on the context and duration of the
behavioral response, many of which
would not be expected to have
deleterious impacts on the fitness of any
individuals. In determining whether the
expected takes will have a negligible
impact, in addition to considering
estimates of the number of marine
mammals that might be ‘‘taken’’, NMFS
must consider other factors, such as the
likely nature of any responses (their
intensity, duration, etc.), the context of
any responses (critical reproductive
time or location, migration, etc.), as well
as the number and nature (e.g., severity)
of estimated Level A harassment takes,
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the number of estimated mortalities, and
the status of the species.
To avoid repetition, we provide some
general analysis immediately below that
applies to all the species listed in Table
5, given that some of the anticipated
effects (or lack thereof) of the Navy’s
training activities on marine mammals
are expected to be relatively similar in
nature. However, below that, we break
our analysis into species to provide
more specific information related to the
anticipated effects on individuals or
where there is information about the
status or structure of any species that
would lead to a differing assessment of
the effects on the population.
Behavioral Harassment
As discussed previously in this
document, marine mammals can
respond to MFAS/HFAS in many
different ways, a subset of which
qualifies as harassment (see Behavioral
Harassment). One thing that the Level B
harassment take estimates do not take
into account is the fact that most marine
mammals will likely avoid strong sound
sources to one extent or another.
Although an animal that avoids the
sound source will likely still be taken in
some instances (such as if the avoidance
results in a missed opportunity to feed,
interruption of reproductive behaviors,
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etc.), in other cases avoidance may
result in fewer instances of take than
were estimated or in the takes resulting
from exposure to a lower received level
than was estimated, which could result
in a less severe response. An animal’s
exposure to a higher received level is
more likely to result in a behavioral
response that is more likely to adversely
affect the health of the animal.
Specifically, given a range of
behavioral responses that may be
classified as Level B harassment, to the
degree that higher received levels are
expected to result in more severe
behavioral responses, only a small
percentage of the anticipated Level B
harassment from Navy activities might
necessarily be expected to potentially
result in more severe responses,
especially when the distance from the
source at which the levels below are
received is considered. Marine
mammals are able to discern the
distance of a given sound source, and
given other equal factors (including
received level), they have been reported
to respond more to sounds that are
closer (DeRuiter et al., 2013). Further,
the estimated number of responses do
not reflect either the duration or context
of those anticipated responses, some of
which will be of very short duration,
and other factors should be considered
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when predicting how the estimated
takes may affect individual fitness.
Although the Navy has been
monitoring the effects of MFAS/HFAS
on marine mammals since 2006, and
research on the effects of active sonar is
advancing, our understanding of exactly
how marine mammals in the Study Area
will respond to MFAS/HFAS is still
growing. The Navy has submitted
reports from more than 60 major
exercises across Navy range complexes
that indicate no behavioral disturbance
was observed. One cannot conclude
from these results that marine mammals
were not harassed from MFAS/HFAS, as
a portion of animals within the area of
concern were not seen, the full series of
behaviors that would more accurately
show an important change is not
typically seen (i.e., only the surface
behaviors are observed), and some of the
non-biologist watchstanders might not
be well-qualified to characterize
behaviors. However, one can say that
the animals that were observed did not
respond in any of the obviously more
severe ways, such as panic, aggression,
or anti-predator response.
Diel Cycle
As noted previously, many animals
perform vital functions, such as feeding,
resting, traveling, and socializing on a
diel cycle (24-hour cycle). Behavioral
reactions to noise exposure (when
taking place in a biologically important
context, such as disruption of critical
life functions, displacement, or
avoidance of important habitat) are
more likely to be significant if they last
more than one diel cycle or recur on
subsequent days (Southall et al., 2007).
Consequently, a behavioral response
lasting less than one day and not
recurring on subsequent days is not
considered severe unless it could
directly affect reproduction or survival
(Southall et al., 2007). Note that there is
a difference between multiple-day
substantive behavioral reactions and
multiple-day anthropogenic activities.
For example, just because at-sea
exercises last for multiple days does not
necessarily mean that individual
animals are either exposed to those
exercises for multiple days or, further,
exposed in a manner resulting in a
sustained multiple day substantive
behavioral response. Additionally, the
Navy does not necessarily operate active
sonar the entire time during an exercise.
While it is certainly possible that these
sorts of exercises could overlap with
individual marine mammals multiple
days in a row at levels above those
anticipated to result in a take, because
of the factors mentioned above, it is
considered not to be likely for the
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majority of takes, does not mean that a
behavioral response is necessarily
sustained for multiple days, and still
necessitates the consideration of likely
duration and context to assess any
effects on the individual’s fitness.
TTS
As mentioned previously, TTS can
last from a few minutes to days, be of
varying degree, and occur across various
frequency bandwidths, all of which
determine the severity of the impacts on
the affected individual, which can range
from minor to more severe. The TTS
sustained by an animal is primarily
classified by three characteristics:
1. Frequency—Available data (of midfrequency hearing specialists exposed to
mid- or high-frequency sounds; Southall
et al., 2007) suggest that most TTS
occurs in the frequency range of the
source up to one octave higher than the
source (with the maximum TTS at 1⁄2
octave above). The more powerful MF
sources used have center frequencies
between 3.5 and 8 kHz and the other
unidentified MF sources are, by
definition, less than 10 kHz, which
suggests that TTS induced by any of
these MF sources would be in a
frequency band somewhere between
approximately 2 and 20 kHz. There are
fewer hours of HF source use and the
sounds would attenuate more quickly,
plus they have lower source levels, but
if an animal were to incur TTS from
these sources, it would cover a higher
frequency range (sources are between 20
and 100 kHz, which means that TTS
could range up to 200 kHz; however, HF
systems are typically used less
frequently and for shorter time periods
than surface ship and aircraft MF
systems, so TTS from these sources is
even less likely).
2. Degree of the shift (i.e., by how
many dB the sensitivity of the hearing
is reduced)—Generally, both the degree
of TTS and the duration of TTS will be
greater if the marine mammal is exposed
to a higher level of energy (which would
occur when the peak dB level is higher
or the duration is longer). The threshold
for the onset of TTS was discussed
previously in this document. An animal
would have to approach closer to the
source or remain in the vicinity of the
sound source appreciably longer to
increase the received SEL, which would
be difficult considering the Lookouts
and the nominal speed of an active
sonar vessel (10–15 knots). In the TTS
studies, some using exposures of almost
an hour in duration or up to 217 SEL,
most of the TTS induced was 15 dB or
less, though Finneran et al. (2007)
induced 43 dB of TTS with a 64-second
exposure to a 20 kHz source. However,
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MFAS emits a nominal ping every 50
seconds, and incurring those levels of
TTS is highly unlikely.
3. Duration of TTS (recovery time)—
In the TTS laboratory studies, some
using exposures of almost an hour in
duration or up to 217 SEL, almost all
individuals recovered within 1 day (or
less, often in minutes), although in one
study (Finneran et al., 2007), recovery
took 4 days.
Based on the range of degree and
duration of TTS reportedly induced by
exposures to non-pulse sounds of
energy higher than that to which freeswimming marine mammals in the field
are likely to be exposed during MFAS/
HFAS training exercises in the Study
Area, it is unlikely that marine
mammals would ever sustain a TTS
from active sonar that alters their
sensitivity by more than 20 dB for more
than a few days (and any incident of
TTS would likely be far less severe due
to the short duration of the majority of
the exercises and the speed of a typical
vessel). Also, for the same reasons
discussed in the Diel Cycle section, and
because of the short distance within
which animals would need to approach
the sound source, it is unlikely that
animals would be exposed to the levels
necessary to induce TTS in subsequent
time periods such that their recovery is
impeded. Additionally, though the
frequency range of TTS that marine
mammals might sustain would overlap
with some of the frequency ranges of
their vocalization types, the frequency
range of TTS from MFAS/HFAS (the
source from which TTS would most
likely be sustained because the higher
source level and slower attenuation
make it more likely that an animal
would be exposed to a higher received
level) would not usually span the entire
frequency range of one vocalization
type, much less span all types of
vocalizations or other critical auditory
cues. If impaired, marine mammals
would typically be aware of their
impairment and are sometimes able to
implement behaviors to compensate (see
Acoustic Masking or Communication
Impairment section), though these
compensations may incur energetic
costs.
Acoustic Masking or Communication
Impairment
Masking only occurs during the time
of the signal (and potential secondary
arrivals of indirect rays), versus TTS,
which continues beyond the duration of
the signal. Standard MFAS/HFAS
nominally pings every 50 seconds for
hull-mounted sources. For the sources
for which we know the pulse length,
most are significantly shorter than hull-
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mounted active sonar, on the order of
several microseconds to tens of
microseconds. For hull-mounted active
sonar, though some of the vocalizations
that marine mammals make are less
than one second long, there is only a 1
in 50 chance that they would occur
exactly when the ping was received, and
when vocalizations are longer than one
second, only parts of them are masked.
Alternately, when the pulses are only
several microseconds long, the majority
of most animals’ vocalizations would
not be masked. Masking effects from
MFAS/HFAS are expected to be
minimal. If masking or communication
impairment were to occur briefly, it
would be in the frequency range of
MFAS/HFAS, which overlaps with
some marine mammal vocalizations;
however, it would likely not mask the
entirety of any particular vocalization,
communication series, or other critical
auditory cue, because the signal length,
frequency, and duty cycle of the MFAS/
HFAS signal does not perfectly mimic
the characteristics of any marine
mammal’s vocalizations.
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Important Marine Mammal Habitat
No critical habitat for marine
mammals species protected under the
ESA has been designated in the Study
Area. There are also no known specific
breeding or calving areas for marine
mammals within the Study Area.
Species-Specific Analysis
Long-beaked Common Dolphin—
Long-beaked common dolphins that
may be found in the Study Area belong
to the California stock (Carretta et al.,
2014). The Navy’s acoustic analysis
(quantitative modeling) predicts that 8
instances of Level B harassment of longbeaked common dolphin may occur
from active sonar in the Study Area
during Civilian Port Defense training
activities. These Level B takes are
anticipated to be in the form of
behavioral reactions (3) and TTS (5) and
no injurious takes of long-beaked
common dolphin are requested or
proposed for authorization. Relative to
population size, these activities are
anticipated to result only in a limited
number of level B harassment takes.
When the numbers of behavioral takes
are compared to the estimated stock
abundance (stock abundance estimates
are shown in Table 1) and if one
assumes that each take happens to a
separate animal, less than 0.01 percent
of the California stock of long-beaked
common dolphin would be behaviorally
harassed during proposed training
activities.
Behavioral reactions of marine
mammals to sound are known to occur
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but are difficult to predict. Recent
behavioral studies indicate that
reactions to sounds, if any, are highly
contextual and vary between species
and individuals within a species
(Moretti et al., 2010; Southall et al.,
2011; Thompson et al., 2010; Tyack,
2009; Tyack et al., 2011). Behavioral
responses can range from alerting, to
changing their behavior or
vocalizations, to avoiding the sound
source by swimming away or diving
(Richardson, 1995; Nowacek, 2007;
Southall et al., 2007; Finneran and
Jenkins, 2012). Long-beaked common
dolphins generally travel in large pods
and should be visible from a distance in
order to implement mitigation measures
and reduce potential impacts. Many of
the recorded long-beaked common
dolphin vocalizations overlap with the
MFAS/HFAS TTS frequency range (2–
20 kHz) (Moore and Ridgway, 1995;
Ketten, 1998); however, NMFS does not
anticipate TTS of a serious degree or
extended duration to occur as a result of
exposure to MFAS/HFAS. Recovery
from a threshold shift (TTS) can take a
few minutes to a few days, depending
on the exposure duration, sound
exposure level, and the magnitude of
the initial shift, with larger threshold
shifts and longer exposure durations
requiring longer recovery times
(Finneran et al., 2005; Mooney et al.,
2009a; Mooney et al., 2009b; Finneran
and Schlundt, 2010). Large threshold
shifts are not anticipated for these
activities because of the unlikelihood
that animals will remain within the
ensonified area at high levels for the
duration necessary to induce larger
threshold shifts. Threshold shifts do not
necessarily affect all hearing frequencies
equally, so some threshold shifts may
not interfere with an animal’s hearing of
biologically relevant sounds.
Overall, the number of predicted
behavioral reactions is low and
temporary behavioral reactions in longbeaked common dolphins are unlikely
to cause long-term consequences for
individual animals or the population.
The Civilian Port Defense activities are
not expected to occur in an area/time of
specific importance for reproductive,
feeding, or other known critical
behaviors for long-beaked common
dolphin. No evidence suggests any
major reproductive differences in
comparison to short-beaked common
dolphins (Reeves et al., 2002). Shortbeaked common dolphin gestation is
approximately 11 to 11.5 months in
duration (Danil, 2004; Murphy and
Rogan, 2006) with most calves born
from May to September (Murphy and
Rogan, 2006). Therefore, calving would
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not occur during the Civilian Port
Defense training timeframe. The
California stock of long-beaked common
dolphin is not depleted under the
MMPA. Although there is no formal
statistical trend analysis, over the last 30
years sighting and stranding data shows
an increasing trend of long-beaked
common dolphins in California waters
(Carretta et al., 2014). Consequently, the
activities are not expected to adversely
impact annual rates of recruitment or
survival of long-beaked common
dolphin.
Short-beaked Common Dolphin—
Short-beaked common dolphins that
may be found in the Study Area belong
to the California/Washington/Oregon
stock (Carretta et al., 2014). The Navy’s
acoustic analysis (quantitative
modeling) predicts that 727 instances of
Level B harassment of short-beaked
common dolphin may occur from active
sonar in the Study Area during Civilian
Port Defense training activities. These
Level B takes are anticipated to be in the
form of behavioral reactions (422) and
TTS (305) and no injurious takes of
short-beaked common dolphin are
requested or proposed for authorization.
Relative to population size, these
activities are anticipated to result only
in a limited number of level B
harassment takes. When the numbers of
behavioral takes are compared to the
estimated stock abundance (stock
abundance estimates are shown in Table
1) and if one assumes that each take
happens to a separate animal, less than
0.18 percent of the California/
Washington/Oregon stock of shortbeaked common dolphin would be
behaviorally harassed during proposed
training activities.
Behavioral reactions of marine
mammals to sound are known to occur
but are difficult to predict. Recent
behavioral studies indicate that
reactions to sounds, if any, are highly
contextual and vary between species
and individuals within a species
(Moretti et al., 2010; Southall et al.,
2011; Thompson et al., 2010; Tyack,
2009; Tyack et al., 2011). Behavioral
responses can range from alerting, to
changing their behavior or
vocalizations, to avoiding the sound
source by swimming away or diving
(Richardson, 1995; Nowacek, 2007;
Southall et al., 2007; Finneran and
Jenkins, 2012). Short-beaked common
dolphins generally travel in large pods
and should be visible from a distance in
order to implement mitigation measures
and reduce potential impacts. Many of
the recorded short-beaked common
dolphin vocalizations overlap with the
MFAS/HFAS TTS frequency range (2–
20 kHz) (Moore and Ridgway, 1995;
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Ketten, 1998); however, NMFS does not
anticipate TTS of a serious degree or
extended duration to occur as a result of
exposure to MFAS/HFAS. Recovery
from a threshold shift (TTS) can take a
few minutes to a few days, depending
on the exposure duration, sound
exposure level, and the magnitude of
the initial shift, with larger threshold
shifts and longer exposure durations
requiring longer recovery times
(Finneran et al., 2005; Mooney et al.,
2009a; Mooney et al., 2009b; Finneran
and Schlundt, 2010). Large threshold
shifts are not anticipated for these
activities because of the unlikelihood
that animals will remain within the
ensonified area at high levels for the
duration necessary to induce larger
threshold shifts. Threshold shifts do not
necessarily affect all hearing frequencies
equally, so some threshold shifts may
not interfere with an animal’s hearing of
biologically relevant sounds.
Overall, the number of predicted
behavioral reactions is low and
temporary behavioral reactions in shortbeaked common dolphins are unlikely
to cause long-term consequences for
individual animals or the population.
The Civilian Port Defense activities are
not expected to occur in an area/time of
specific importance for reproductive,
feeding, or other known critical
behaviors for long-beaked common
dolphin. Short-beaked common dolphin
gestation is approximately 11 to 11.5
months in duration (Danil, 2004;
Murphy and Rogan, 2006) with most
calves born from May to September
(Murphy and Rogan, 2006). Therefore,
calving would not occur during the
Civilian Port Defense training
timeframe. The California/Washington/
Oregon stock of short-beaked common
dolphin is not depleted under the
MMPA. Abundance off California has
increased dramatically since the late
1970s, along with a smaller decrease in
abundance in the eastern tropical
Pacific, suggesting a large-scale
northward shift in the distribution of
this species in the eastern north Pacific
(Forney and Barlow, 1998; Forney et al.,
1995). Consequently, the activities are
not expected to adversely impact annual
rates of recruitment or survival of shortbeaked common dolphin.
Risso’s Dolphin—Risso’s dolphins
that may be found in the Study Area
belong to the California/Washington/
Oregon stock (Carretta et al., 2014). The
Navy’s acoustic analysis (quantitative
modeling) predicts that 21 instances of
Level B harassment of Risso’s dolphin
may occur from active sonar in the
Study Area during Civilian Port Defense
training activities. These Level B takes
are anticipated to be in the form of
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behavioral reactions (16) and TTS (5)
and no injurious takes of Risso’s
dolphin are requested or proposed for
authorization. Relative to population
size, these activities are anticipated to
result only in a limited number of level
B harassment takes. When the numbers
of behavioral takes are compared to the
estimated stock abundance (stock
abundance estimates are shown in Table
1) and if one assumes that each take
happens to a separate animal,
approximately 0.33 percent of the
California/Washington/Oregon stock of
Risso’s dolphin would be behaviorally
harassed during proposed training
activities.
Behavioral reactions of marine
mammals to sound are known to occur
but are difficult to predict. Recent
behavioral studies indicate that
reactions to sounds, if any, are highly
contextual and vary between species
and individuals within a species
(Moretti et al., 2010; Southall et al.,
2011; Thompson et al., 2010; Tyack,
2009; Tyack et al., 2011). Behavioral
responses can range from alerting, to
changing their behavior or
vocalizations, to avoiding the sound
source by swimming away or diving
(Richardson, 1995; Nowacek, 2007;
Southall et al., 2007; Finneran and
Jenkins, 2012). Risso’s dolphins
generally travel in large pods and
should be visible from a distance in
order to implement mitigation measures
and reduce potential impacts. Many of
the recorded Risso’s dolphin
vocalizations overlap with the MFAS/
HFAS TTS frequency range (2–20 kHz)
(Corkeron and Van Parijs 2001);
however, NMFS does not anticipate TTS
of a serious degree or extended duration
to occur as a result of exposure to
MFAS/HFAS. Recovery from a
threshold shift (TTS) can take a few
minutes to a few days, depending on the
exposure duration, sound exposure
level, and the magnitude of the initial
shift, with larger threshold shifts and
longer exposure durations requiring
longer recovery times (Finneran et al.,
2005; Mooney et al., 2009a; Mooney et
al., 2009b; Finneran and Schlundt,
2010). Large threshold shifts are not
anticipated for these activities because
of the unlikelihood that animals will
remain within the ensonified area at
high levels for the duration necessary to
induce larger threshold shifts.
Threshold shifts do not necessarily
affect all hearing frequencies equally, so
some threshold shifts may not interfere
with an animal’s hearing of biologically
relevant sounds.
Overall, the number of predicted
behavioral reactions is low and
temporary behavioral reactions in
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Risso’s dolphins are unlikely to cause
long-term consequences for individual
animals or the population. The Civilian
Port Defense activities are not expected
to occur in an area/time of specific
importance for reproductive, feeding, or
other known critical behaviors for
Risso’s dolphin. The California/
Washington/Oregon stock of Risso’s
dolphin is not depleted under the
MMPA. The distribution of Risso’s
dolphins throughout the region is highly
variable, apparently in response to
oceanographic changes (Forney and
Barlow, 1998). The status of Risso’s
dolphins off California, Oregon and
Washington relative to optimum
sustainable population is not known,
and there are insufficient data to
evaluate potential trends in abundance.
However, Civilian Port Defense training
activities are not expected to adversely
impact annual rates of recruitment or
survival of Risso’s dolphin for the
reasons stated above.
Pacific White-Sided Dolphin—Pacific
white-sided dolphins that may be found
in the Study Area belong to the
California/Washington/Oregon stock
(Carretta et al., 2014). The Navy’s
acoustic analysis (quantitative
modeling) predicts that 40 instances of
Level B harassment of Pacific whitesided dolphin may occur from active
sonar in the Study Area during Civilian
Port Defense training activities. These
Level B takes are anticipated to be in the
form of behavioral reactions (21) and
TTS (19) and no injurious takes of
Pacific white-sided dolphin are
requested or proposed for authorization.
Relative to population size, these
activities are anticipated to result only
in a limited number of level B
harassment takes. When the numbers of
behavioral takes are compared to the
estimated stock abundance (stock
abundance estimates are shown in Table
1) and if one assumes that each take
happens to a separate animal, less than
0.15 percent of the California/
Washington/Oregon stock of Pacific
white-sided dolphin would be
behaviorally harassed during proposed
training activities.
Behavioral reactions of marine
mammals to sound are known to occur
but are difficult to predict. Recent
behavioral studies indicate that
reactions to sounds, if any, are highly
contextual and vary between species
and individuals within a species
(Moretti et al., 2010; Southall et al.,
2011; Thompson et al., 2010; Tyack,
2009; Tyack et al., 2011). Behavioral
responses can range from alerting, to
changing their behavior or
vocalizations, to avoiding the sound
source by swimming away or diving
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(Richardson, 1995; Nowacek, 2007;
Southall et al., 2007; Finneran and
Jenkins, 2012). Pacific white-sided
dolphins generally travel in large pods
and should be visible from a distance in
order to implement mitigation measures
and reduce potential impacts. Many of
the recorded Pacific white-sided
dolphin vocalizations overlap with the
MFAS/HFAS TTS frequency range (2–
20 kHz); however, NMFS does not
anticipate TTS of a serious degree or
extended duration to occur as a result of
exposure to MFAS/HFAS. Recovery
from a threshold shift (TTS) can take a
few minutes to a few days, depending
on the exposure duration, sound
exposure level, and the magnitude of
the initial shift, with larger threshold
shifts and longer exposure durations
requiring longer recovery times
(Finneran et al., 2005; Mooney et al.,
2009a; Mooney et al., 2009b; Finneran
and Schlundt, 2010). Large threshold
shifts are not anticipated for these
activities because of the unlikelihood
that animals will remain within the
ensonified area at high levels for the
duration necessary to induce larger
threshold shifts. Threshold shifts do not
necessarily affect all hearing frequencies
equally, so some threshold shifts may
not interfere with an animal’s hearing of
biologically relevant sounds.
Overall, the number of predicted
behavioral reactions is low and
temporary behavioral reactions in
Pacific white-sided dolphins are
unlikely to cause long-term
consequences for individual animals or
the population. The Civilian Port
Defense activities are not expected to
occur in an area/time of specific
importance for reproductive, feeding, or
other known critical behaviors for longbeaked common dolphin. Pacific whitesided dolphin calves are typically born
in the summer months between April
and early September (Black, 1994;
NOAA, 2012; Reidenberg and Laitman,
2002). This species is predominantly
located around the proposed Study Area
in the colder winter months when
neither mating nor calving is expected,
as both occur off the coast of Oregon
and Washington outside of the
timeframe for the proposed activities
(October through November). The
California/Washington/Oregon stock of
Pacific white-sided dolphin is not
depleted under the MMPA. The stock is
considered stable, with no indications
of any positive or negative trends in
abundance (NOAA, 2014).
Consequently, the activities are not
expected to adversely impact annual
rates of recruitment or survival of
Pacific white-sided dolphin.
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Bottlenose Dolphin—Bottlenose
dolphins that may be found in the Study
Area belong to the California Coastal
stock (Carretta et al., 2014). The Navy’s
acoustic analysis (quantitative
modeling) predicts that 48 instances of
Level B harassment of bottlenose
dolphin may occur from active sonar in
the Study Area during Civilian Port
Defense training activities. These Level
B takes are anticipated to be in the form
of behavioral reactions (29) and TTS
(19) and no injurious takes of bottlenose
dolphin are requested or proposed for
authorization. Relative to population
size, these activities are anticipated to
result only in a limited number of level
B harassment takes. When the numbers
of behavioral takes are compared to the
estimated stock abundance (stock
abundance estimates are shown in Table
1) and if one assumes that each take
happens to a separate animal, less than
15 percent of the Coastal stock of
bottlenose dolphin would be
behaviorally harassed during proposed
training activities.
Behavioral reactions of marine
mammals to sound are known to occur
but are difficult to predict. Recent
behavioral studies indicate that
reactions to sounds, if any, are highly
contextual and vary between species
and individuals within a species
(Moretti et al., 2010; Southall et al.,
2011; Thompson et al., 2010; Tyack,
2009; Tyack et al., 2011). Behavioral
responses can range from alerting, to
changing their behavior or
vocalizations, to avoiding the sound
source by swimming away or diving
(Richardson, 1995; Nowacek, 2007;
Southall et al., 2007; Finneran and
Jenkins, 2012). Bottlenose dolphins
generally travel in large pods and
should be visible from a distance in
order to implement mitigation measures
and reduce potential impacts. Many of
the recorded bottlenose dolphin
vocalizations overlap with the MFAS/
HFAS TTS frequency range (2–20 kHz);
however, NMFS does not anticipate TTS
of a serious degree or extended duration
to occur as a result of exposure to
MFAS/HFAS. Recovery from a
threshold shift (TTS) can take a few
minutes to a few days, depending on the
exposure duration, sound exposure
level, and the magnitude of the initial
shift, with larger threshold shifts and
longer exposure durations requiring
longer recovery times (Finneran et al.,
2005; Mooney et al., 2009a; Mooney et
al., 2009b; Finneran and Schlundt,
2010). Large threshold shifts are not
anticipated for these activities because
of the unlikelihood that animals will
remain within the ensonified area at
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53685
high levels for the duration necessary to
induce larger threshold shifts.
Threshold shifts do not necessarily
affect all hearing frequencies equally, so
some threshold shifts may not interfere
with an animal’s hearing of biologically
relevant sounds.
Overall, the number of predicted
behavioral reactions is low and
temporary behavioral reactions in
bottlenose dolphins are unlikely to
cause long-term consequences for
individual animals or the population.
The Civilian Port Defense activities are
not expected to occur in an area/time of
specific importance for reproductive,
feeding, or other known critical
behaviors for bottlenose dolphin. The
California/Washington/Oregon stock of
bottlenose dolphin is not depleted
under the MMPA. In a comparison of
abundance estimates from 1987–89 (n =
354), 1996–98 (n = 356), and 2004–05 (n
= 323), Dudzik et al. (2006) found that
the population size has remained stable
over this period of approximately 20
years. Consequently, the activities are
not expected to adversely impact annual
rates of recruitment or survival of
bottlenose dolphin.
Harbor Seal—Harbor seals that may
be found in the Study Area belong to the
California stock (Carretta et al., 2014).
Harbor seals have not been observed on
the mainland coast of Los Angeles,
Orange, and northern San Diego
Counties (Henkel and Harvey, 2008;
Lowry et al., 2008). Thus, no harbor seal
haul-outs are located within the
proposed Study Area. The Navy’s
acoustic analysis (quantitative
modeling) predicts that 8 instances of
Level B harassment of harbor seal may
occur from active sonar in the Study
Area during Civilian Port Defense
training activities. These Level B takes
are anticipated to be in the form of nonTTS behavioral reactions only and no
injurious takes of harbor seal are
requested or proposed for authorization.
Relative to population size, these
activities are anticipated to result only
in a limited number of level B
harassment takes. When the numbers of
behavioral takes are compared to the
estimated stock abundance (stock
abundance estimates are shown in Table
1) and if one assumes that each take
happens to a separate animal, less than
0.03 percent of the California stock of
harbor seal would be behaviorally
harassed during proposed training
activities.
Research and observations show that
pinnipeds in the water may be tolerant
of anthropogenic noise and activity (a
review of behavioral reactions by
pinnipeds to impulsive and nonimpulsive noise can be found in
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Richardson et al., 1995 and Southall et
al., 2007). Available data, though
limited, suggest that exposures between
approximately 90 and 140 dB SPL do
not appear to induce strong behavioral
responses in pinnipeds exposed to
nonpulse sounds in water (Jacobs and
Terhune, 2002; Costa et al., 2003;
Kastelein et al., 2006c). Based on the
limited data on pinnipeds in the water
exposed to multiple pulses (small
explosives, impact pile driving, and
seismic sources), exposures in the
approximately 150 to 180 dB SPL range
generally have limited potential to
induce avoidance behavior in pinnipeds
(Harris et al., 2001; Blackwell et al.,
2004; Miller et al., 2004). If pinnipeds
are exposed to sonar or other active
acoustic sources they may react in a
number of ways depending on their
experience with the sound source and
what activity they are engaged in at the
time of the acoustic exposure. Pinnipeds
may not react at all until the sound
source is approaching within a few
hundred meters and then may alert,
ignore the stimulus, change their
behaviors, or avoid the immediate area
by swimming away or diving. Effects on
pinnipeds in the Study Area that are
taken by Level B harassment, on the
basis of reports in the literature as well
as Navy monitoring from past activities,
will likely be limited to reactions such
as increased swimming speeds,
increased surfacing time, or decreased
foraging (if such activity were
occurring). Most likely, individuals will
simply move away from the sound
source and be temporarily displaced
from those areas, or not respond at all.
In areas of repeated and frequent
acoustic disturbance, some animals may
habituate or learn to tolerate the new
baseline or fluctuations in noise level.
Habituation can occur when an animal’s
response to a stimulus wanes with
repeated exposure, usually in the
absence of unpleasant associated events
(Wartzok et al., 2003). While some
animals may not return to an area, or
may begin using an area differently due
to training activities, most animals are
expected to return to their usual
locations and behavior. Given their
documented tolerance of anthropogenic
sound (Richardson et al., 1995 and
Southall et al., 2007), repeated
exposures of harbor seals to levels of
sound that may cause Level B
harassment are unlikely to result in
hearing impairment or to significantly
disrupt foraging behavior.
Overall, the number of predicted
behavioral reactions is low and
temporary behavioral reactions in
harbor seals are unlikely to cause long-
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term consequences for individual
animals or the population. The Civilian
Port Defense activities are not expected
to occur in an area/time of specific
importance for reproductive, feeding, or
other known critical behaviors for
harbor seal. In California, harbor seals
breed from March to May and pupping
occurs between April and May (Alden et
al., 2002; Reeves et al., 2002), neither of
which occur within the timeframe of the
proposed activities. The California stock
of harbor seal is not depleted under the
MMPA. Counts of harbor seals in
California increased from 1981 to 2004,
although a review of harbor seal
dynamics through 1991 concluded that
their status could not be determined
with certainty (Hanan, 1996). The
population appears to be stabilizing at
what may be its carrying capacity.
Consequently, the activities are not
expected to adversely impact annual
rates of recruitment or survival of harbor
seal.
California Sea Lion—California sea
lions that may be found in the Study
Area belong to the U.S. stock (Carretta
et al., 2014). The Navy’s acoustic
analysis (quantitative modeling)
predicts that 46 instances of Level B
harassment of California sea lion may
occur from active sonar in the Study
Area during Civilian Port Defense
training activities. These Level B takes
are anticipated to be in the form of nonTTS behavioral reactions only and no
injurious takes of California sea lions
are requested or proposed for
authorization. Relative to population
size, these activities are anticipated to
result only in a limited number of level
B harassment takes. When the numbers
of behavioral takes are compared to the
estimated stock abundance (stock
abundance estimates are shown in Table
1) and if one assumes that each take
happens to a separate animal, less than
0.02 percent of the U.S. stock of
California sea lions would be
behaviorally harassed during proposed
training activities.
Research and observations show that
pinnipeds in the water may be tolerant
of anthropogenic noise and activity (a
review of behavioral reactions by
pinnipeds to impulsive and nonimpulsive noise can be found in
Richardson et al., 1995 and Southall et
al., 2007). Available data, though
limited, suggest that exposures between
approximately 90 and 140 dB SPL do
not appear to induce strong behavioral
responses in pinnipeds exposed to
nonpulse sounds in water (Jacobs and
Terhune, 2002; Costa et al., 2003;
Kastelein et al., 2006c). Based on the
limited data on pinnipeds in the water
exposed to multiple pulses (small
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explosives, impact pile driving, and
seismic sources), exposures in the
approximately 150 to 180 dB SPL range
generally have limited potential to
induce avoidance behavior in pinnipeds
(Harris et al., 2001; Blackwell et al.,
2004; Miller et al., 2004). If pinnipeds
are exposed to sonar or other active
acoustic sources they may react in a
number of ways depending on their
experience with the sound source and
what activity they are engaged in at the
time of the acoustic exposure. Pinnipeds
may not react at all until the sound
source is approaching within a few
hundred meters and then may alert,
ignore the stimulus, change their
behaviors, or avoid the immediate area
by swimming away or diving. Effects on
pinnipeds in the Study Area that are
taken by Level B harassment, on the
basis of reports in the literature as well
as Navy monitoring from past activities
will likely be limited to reactions such
as increased swimming speeds,
increased surfacing time, or decreased
foraging (if such activity were
occurring). Most likely, individuals will
simply move away from the sound
source and be temporarily displaced
from those areas, or not respond at all.
In areas of repeated and frequent
acoustic disturbance, some animals may
habituate or learn to tolerate the new
baseline or fluctuations in noise level.
Habituation can occur when an animal’s
response to a stimulus wanes with
repeated exposure, usually in the
absence of unpleasant associated events
(Wartzok et al., 2003). While some
animals may not return to an area, or
may begin using an area differently due
to training activities, most animals are
expected to return to their usual
locations and behavior. Given their
documented tolerance of anthropogenic
sound (Richardson et al., 1995 and
Southall et al., 2007), repeated
exposures of individuals to levels of
sound that may cause Level B
harassment are unlikely to result in
hearing impairment or to significantly
disrupt foraging behavior.
Overall, the number of predicted
behavioral reactions is low and
temporary behavioral reactions in
California sea lions are unlikely to cause
long-term consequences for individual
animals or the population. The Civilian
Port Defense activities are not expected
to occur in an area/time of specific
importance for reproductive, feeding, or
other known critical behaviors for
California sea lions. It is likely that male
California sea lions will be primarily
outside of the Study Area during the
timeframe of the proposed activities, but
females may be present. Typically
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during the summer, California sea lions
congregate near rookery islands and
specific open-water areas. The primary
rookeries off the coast of California are
on San Nicolas, San Miguel, Santa
Barbara, and San Clemente Islands
(Boeuf and Bonnell, 1980; Carretta et al.,
2000; Lowry et al., 1992; Lowry and
Forney, 2005). In May or June, female
sea lions give birth, either on land or in
water. Adult males establish breeding
territories, both on land and in water,
from May to July. In addition to the
rookery sites, Santa Catalina Island is a
major haul-out site within the Southern
California Bight (Boeuf, 2002). Thus,
breeding and pupping take place
outside of the timeframe and location of
the proposed training activities. The
U.S. stock of California sea lions is not
depleted under the MMPA. A regression
of the natural logarithm of the pup
counts against year indicates that the
counts of pups increased at an annual
rate of 5.4 percent between 1975 and
˜
2008 (when pup counts for El Nino
years were removed from the 1975–2005
time series). These records of pup
counts from 1975 to 2008 were
compiled from Lowry and MaravillaChavez (2005) and unpublished NMFS
data. Consequently, the activities are not
expected to adversely impact annual
rates of recruitment or survival of
California sea lion.
Preliminary Determination
Overall, the conclusions and
predicted exposures in this analysis find
that overall impacts on marine mammal
species and stocks would be negligible
for the following reasons:
• All estimated acoustic harassments
for the proposed Civilian Port Defense
training activities are within the noninjurious temporary threshold shift
(TTS) or behavioral effects zones (Level
B harassment), and these harassments
(take numbers) represent only a small
percentage (less than 15 percent of
bottlenose dolphin coastal stock; less
than 0.5 percent for all other species) of
the respective stock abundance for each
species taken.
• Marine mammal densities inputted
into the model are also overly
conservative, particularly when
considering species where data is
limited in portions of the proposed
study area and seasonal migrations
extend throughout the Study Area.
• The protective measures described
in Proposed Mitigation are designed to
reduce sound exposure on marine
mammals to levels below those that may
cause physiological effects (injury).
• Animals exposed to acoustics from
this two week event are habituated to a
bustling industrial port environment.
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This proposed IHA assumes that
short-term non-injurious SELs predicted
to cause onset-TTS or predicted SPLs
predicted to cause temporary behavioral
disruptions (non-TTS) qualify as Level
B harassment. This approach
predominately overestimates
disturbances from acoustic
transmissions as qualifying as
harassment under MMPA’s definition
for military readiness activities because
there is no established scientific
correlation between short term sonar
use and long term abandonment or
significant alteration of behavioral
patterns in marine mammals.
Consideration of negligible impact is
required for NMFS to authorize
incidental take of marine mammals. By
definition, an activity has a ‘‘negligible
impact’’ on a species or stock when it
is determined that the total taking is not
likely to reduce annual rates of adult
survival or recruitment (i.e., offspring
survival, birth rates).
Behavioral reactions of marine
mammals to sound are known to occur
but are difficult to predict. Recent
behavioral studies indicate that
reactions to sounds, if any, are highly
contextual and vary between species
and individuals within a species
(Moretti et al., 2010; Southall et al.,
2011; Thompson et al., 2010; Tyack,
2009; Tyack et al., 2011). Depending on
the context, marine mammals often
change their activity when exposed to
disruptive levels of sound. When sound
becomes potentially disruptive,
cetaceans at rest become active, feeding
or socializing cetaceans or pinnipeds
often interrupt these events by diving or
swimming away. If the sound
disturbance occurs around a haul out
site, pinnipeds may move back and
forth between water and land or
eventually abandon the haul out. When
attempting to understand behavioral
disruption by anthropogenic sound, a
key question to ask is whether the
exposures have biologically significant
consequences for the individual or
population (National Research Council
of the National Academies, 2005).
If a marine mammal does react to an
underwater sound by changing its
behavior or moving a small distance, the
impacts of the change may not be
detrimental to the individual. For
example, researchers have found during
a study focusing on dolphins response
to whale watching vessels in New
Zealand, that when animals can cope
with constraint and easily feed or move
elsewhere, there’s little effect on
survival (Lusseau and Bejder, 2007). On
the other hand, if a sound source
displaces marine mammals from an
important feeding or breeding area for a
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53687
prolonged period and they do not have
an alternate equally desirable area,
impacts on the marine mammal could
be negative because the disruption has
biological consequences. Biological
parameters or key elements having
greatest importance to a marine
mammal relate to its ability to mature,
reproduce, and survive. For example,
some elements that should be
considered include the following:
• Growth: Adverse effects on ability
to feed;
• Reproduction: The range at which
reproductive displays can be heard and
the quality of mating/calving grounds;
and
• Survival: Sound exposure may
directly affect survival, for example
where sources of a certain type are
deployed in a a manner that could lead
to a stranding response.
The importance of the disruption and
degree of consequence for individual
marine mammals often has much to do
with the frequency, intensity, and
duration of the disturbance. Isolated
acoustic disturbances such as acoustic
transmissions usually have minimal
consequences or no lasting effects for
marine mammals. Marine mammals
regularly cope with occasional
disruption of their activities by
predators, adverse weather, and other
natural phenomena. It is also reasonable
to assume that they can tolerate
occasional or brief disturbances by
anthropogenic sound without
significant consequences.
The exposure estimates calculated by
predictive models currently available
reliably predict propagation of sound
and received levels and measure a shortterm, immediate response of an
individual using applicable criteria.
Consequences to populations are much
more difficult to predict and empirical
measurement of population effects from
anthropogenic stressors is limited
(National Research Council of the
National Academies, 2005). To predict
indirect, long-term, and cumulative
effects, the processes must be well
understood and the underlying data
available for models. Based on each
species’ life history information,
expected behavioral patterns in the
Study Area, all of the modeled
exposures resulting in temporary
behavioral disturbance (Table 5), and
the application of mitigation procedures
proposed above, the proposed Civilian
Port Defense activities are anticipated to
have a negligible impact on marine
mammal stocks within the Study Area.
NMFS concludes that Civilian Port
Defense training activities within the
Study Area would result in Level B
takes only, as summarized in Table 5.
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The effects of these military readiness
activities will be limited to short-term,
localized changes in behavior and
possible temporary threshold shift in
the hearing of marine mammal species.
These effects are not likely to have a
significant or long-term impact on
feeding, breeding, or other important
biological functions. No take by injury
or mortality is anticipated, and the
potential for permanent hearing
impairment is unlikely. Based on best
available science NMFS concludes that
exposures to marine mammal species
and stocks due to the proposed training
activities would result in only shortterm effects from those Level B takes to
most individuals exposed and would
likely not affect annual rates of
recruitment or survival.
Based on the analysis contained
herein of the likely effects of the
specified activity on marine mammals
and their habitat and dependent upon
the implementation of the mitigation
and monitoring measures, NMFS
preliminarily finds that the total taking
from Civilian Port Defense training
activities in the Study Area will have a
negligible impact on the affected species
or stocks.
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Subsistence Harvest of Marine
Mammals
There are no relevant subsistence uses
of marine mammals implicated by this
action. Therefore, NMFS has
determined that the total taking of
affected species or stocks would not
have an unmitigable adverse impact on
the availability of such species or stocks
for taking for subsistence purposes.
NEPA
The Navy is preparing an EA in
accordance with the National
Environmental Policy Act (NEPA), to
evaluate all components of the proposed
Civilian Port Defense training activities.
NMFS intends to adopt the Navy’s EA,
if adequate and appropriate. Currently,
we believe that the adoption of the
Navy’s EA will allow NMFS to meet its
responsibilities under NEPA for the
issuance of an IHA to the Navy for
Civilian Port Defense activities at the
Ports of Los Angeles and Long Beach
Harbor. If necessary, however, NMFS
will supplement the existing analysis to
ensure that we comply with NEPA prior
to the issuance of the final IHA.
ESA
No species listed under the
Endangered Species Act (ESA) are
expected to be affected by the proposed
Civilian Port Defense training activities
and no takes of any ESA-listed species
are requested or proposed for
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authorization under the MMPA.
Therefore, NMFS has determined that a
formal section 7 consultation under the
ESA is not required.
Proposed Authorization
As a result of these preliminary
determinations, NMFS proposes to issue
an IHA to the Navy for conducting
Civilian Port Defense activities from
October to November 2015 on the U.S.
west coast near Los Angeles/Long
Beach, California, provided the
previously mentioned mitigation,
monitoring, and reporting requirements
are incorporated. The proposed IHA
language is provided next.
This section contains a draft of the
IHA itself. The wording contained in
this section is proposed for inclusion in
the IHA (if issued).
The Commander, U.S. Pacific Fleet,
250 Makalapa Drive, Pearl Harbor,
Hawaii 96860, and persons operating
under his authority (i.e., Navy), is
hereby authorized under section
101(a)(5)(D) of the Marine Mammal
Protection Act (16 U.S.C. 1371(a)(5)(D))
and 50 CFR 216.107, to harass marine
mammals incidental to Civilian Port
Defense training activities proposed to
be conducted near the Ports of Los
Angeles and Long Beach from October
to November 2015.
1. This Authorization is valid from
October 25, 2015 through November 25,
2015.
2. This Authorization is valid for the
incidental taking of a specified number
of marine mammals, incidental to
Civilian Port Defense training activities
proposed to be conducted near the Ports
of Los Angeles and Long Beach from
October to November 2015, as described
in the Incidental Harassment
Authorization (IHA) application.
3. The holder of this authorization
(Holder) is hereby authorized to take, by
Level B harassment only, 8 long-beaked
common dolphins (Delphinus capensis),
727 short-beaked common dolphins
(Delphinus delphis), 21 Risso’s dolphins
(Grampus griseus), 40 Pacific whitesided dolphins (Lagenorhynchus
obilquidens), 48 bottlenose dolphins
(Tursiops truncates), 8 harbor seals
(Phoca vitulina), and 46 California sea
lions (Zalophus californianus)
incidental to Civilian Port Defense
training activities proposed to be
conducted near the Ports of Los Angeles
and Long Beach, California.
4. The taking of any marine mammal
in a manner prohibited under this IHA
must be reported immediately to NMFS’
Office of Protected Resources, 1315
East-West Highway, Silver Spring, MD
20910; phone 301–427–8401; fax 301–
713–0376.
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5. Mitigation Requirements
The Holder is required to abide by the
following mitigation conditions listed in
5(a)–(b). Failure to comply with these
conditions may result in the
modification, suspension, or revocation
of this IHA.
(a) Lookouts
The following are protective measures
concerning the use of Lookouts:
Procedural Measures—The Navy will
have two types of lookouts for the
purposes of conducting visual
observations: (1) Those positioned on
surface ships, and (2) those positioned
in aircraft or on boats. Lookouts
positioned on surface ships will be
dedicated solely to diligent observation
of the air and surface of the water. Their
observation objectives will include, but
are not limited to, detecting the
presence of biological resources and
recreational or fishing boats, observing
mitigation zones, and monitoring for
vessel and personnel safety concerns.
Lookouts positioned in aircraft or on
boats will, to the maximum extent
practicable and consistent with aircraft
and boat safety and training
requirements, comply with the
observation objectives described above
for Lookouts positioned on surface
ships.
Active Sonar—The Navy will have
one Lookout on ships or aircraft
conducting high-frequency active sonar
activities associated with mine warfare
activities at sea.
Vessels—While underway, vessels
will have a minimum of one Lookout.
Towed In-Water Devices—The Navy
will have one Lookout during activities
using towed in-water devices when
towed from a manned platform.
(b) Mitigation Zones—The following
are protective measures concerning the
implementation of mitigation zones:
Active Sonar—Mitigation will include
visual observation from a vessel or
aircraft (with the exception of platforms
operating at high altitudes) immediately
before and during active transmission
within a mitigation zone of 200 yards
(yds. [183 m]) from the active sonar
source. If the source can be turned off
during the activity, active transmission
will cease if a marine mammal is
sighted within the mitigation zone.
Active transmission will recommence if
any one of the following conditions is
met: (1) the animal is observed exiting
the mitigation zone, (2) the animal is
thought to have exited the mitigation
zone based on a determination of its
course and speed and the relative
motion between the animal and the
source, (3) the mitigation zone has been
clear from any additional sightings for a
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period of 10 minutes for an aircraftdeployed source, (4) the mitigation zone
has been clear from any additional
sightings for a period of 30 minutes for
a vessel-deployed source, (5) the vessel
or aircraft has repositioned itself more
than 400 yds (366 m) away from the
location of the last sighting, or (6) the
vessel concludes that dolphins are
deliberately closing in to ride the
vessel’s bow wave (and there are no
other marine mammal sightings within
the mitigation zone).
Vessels—Vessels will avoid
approaching marine mammals head on
and will maneuver to maintain a
mitigation zone of 500 yds (457 m)
around observed whales, and 200 yds
(183 m) around all other marine
mammals (except bow riding dolphins),
providing it is safe to do so.
Towed In-Water Devices—The Navy
will ensure that towed in-water devices
being towed from manned platforms
avoid coming within a mitigation zone
of 250 yds (229 m) around any observed
marine mammal, providing it is safe to
do so.
6. Monitoring and Reporting
Requirements
The Holder is required to abide by the
following monitoring and reporting
conditions. Failure to comply with these
conditions may result in the
modification, suspension, or revocation
of this IHA.
General Notification of Injured or
Dead Marine Mammals—If any injury or
death of a marine mammal is observed
during the Civilian Port Defense training
activity, the Navy will immediately halt
the activity and report the incident to
NMFS following the standard
monitoring and reporting measures
consistent with the MITT EIS/OEIS. The
reporting measures include the
following procedures:
Navy personnel shall ensure that
NMFS (regional stranding coordinator)
is notified immediately (or as soon as
clearance procedures allow) if an
injured or dead marine mammal is
found during or shortly after, and in the
vicinity of, any Navy training activity
utilizing high-frequency active sonar.
The Navy shall provide NMFS with
species or description of the animal(s),
the condition of the animal(s) (including
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carcass condition if the animal is dead),
location, time of first discovery,
observed behaviors (if alive), and photo
or video (if available). The Navy shall
consult the Stranding Response and
Communication Plan to obtain more
specific reporting requirements for
specific circumstances.
Vessel Strike—Vessel strike during
Navy Civilian Port Defense activities in
the Study Area is not anticipated;
however, in the event that a Navy vessel
strikes a whale, the Navy shall do the
following:
Immediately report to NMFS
(pursuant to the established
Communication Protocol) the:
• Species identification (if known);
• Location (latitude/longitude) of the
animal (or location of the strike if the
animal has disappeared);
• Whether the animal is alive or dead
(or unknown); and
• The time of the strike.
As soon as feasible, the Navy shall
report to or provide to NMFS, the:
• Size, length, and description
(critical if species is not known) of
animal;
• An estimate of the injury status
(e.g., dead, injured but alive, injured
and moving, blood or tissue observed in
the water, status unknown, disappeared,
etc.);
• Description of the behavior of the
whale during event, immediately after
the strike, and following the strike (until
the report is made or the animal is no
longer sighted);
• Vessel class/type and operational
status;
• Vessel length;
• Vessel speed and heading; and
• To the best extent possible, obtain
a photo or video of the struck animal,
if the animal is still in view.
Within 2 weeks of the strike, provide
NMFS:
• A detailed description of the
specific actions of the vessel in the 30minute timeframe immediately
preceding the strike, during the event,
and immediately after the strike (e.g.,
the speed and changes in speed, the
direction and changes in direction,
other maneuvers, sonar use, etc., if not
classified);
• A narrative description of marine
mammal sightings during the event and
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53689
immediately after, and any information
as to sightings prior to the strike, if
available; and use established Navy
shipboard procedures to make a camera
available to attempt to capture
photographs following a ship strike.
NMFS and the Navy will coordinate
to determine the services the Navy may
provide to assist NMFS with the
investigation of the strike. The response
and support activities to be provided by
the Navy are dependent on resource
availability, must be consistent with
military security, and must be
logistically feasible without
compromising Navy personnel safety.
Assistance requested and provided may
vary based on distance of strike from
shore, the nature of the vessel that hit
the whale, available nearby Navy
resources, operational and installation
commitments, or other factors.
7. A copy of this Authorization must
be in the possession of the on-site
Commanding Officer in order to take
marine mammals under the authority of
this Incidental Harassment
Authorization while conducting the
specified activities.
8. This Authorization may be
modified, suspended, or withdrawn if
the Holder or any person operating
under his authority fails to abide by the
conditions prescribed herein or if the
authorized taking is having more than a
negligible impact on the species or stock
of affected marine mammals.
Request for Public Comments
NMFS requests comment on our
analysis, the draft authorization, and
any other aspect of the Notice of
Proposed IHA for the Navy’s Civilian
Port Defense training activities. Please
include with your comments any
supporting data or literature citations to
help inform our final decision on the
Navy’s request for an MMPA
authorization.
Dated: August 31, 2015.
Donna S. Wieting,
Director, Office of Protected Resources,
National Marine Fisheries Service.
[FR Doc. 2015–21911 Filed 9–3–15; 8:45 am]
BILLING CODE 3510–22–P
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Agencies

[Federal Register Volume 80, Number 172 (Friday, September 4, 2015)]
[Notices]
[Pages 53657-53689]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-21911]
[[Page 53657]]
Vol. 80
Friday,
No. 172
September 4, 2015
Part III
Department of Commerce
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National Oceanic and Atmospheric Administration
Takes of Marine Mammals Incidental to Specified Activities; U.S. Navy
Civilian Port Defense Activities at the Ports of Los Angeles/Long
Beach, California; Notice
Federal Register / Vol. 80 , No. 172 / Friday, September 4, 2015 /
Notices
[[Page 53658]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XE131
Takes of Marine Mammals Incidental to Specified Activities; U.S.
Navy Civilian Port Defense Activities at the Ports of Los Angeles/Long
Beach, California
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments.
-----------------------------------------------------------------------
SUMMARY: NMFS has received a request from the U.S. Navy (Navy) for an
Incidental Harassment Authorization (IHA) to take marine mammals, by
harassment, incidental to Civilian Port defense activities within and
near the Ports of Los Angeles and Long Beach from October through
November 2015. Pursuant to the Marine Mammal Protection Act (MMPA),
NMFS is requesting comments on its proposal to issue an IHA to the Navy
to incidentally take, by Level B harassment only, marine mammals during
the specified activity.
DATES: Comments and information must be received no later than October
5, 2015.
ADDRESSES: Comments on the Navy's IHA application (the application)
should be addressed to Jolie Harrison, Chief, Permits and Conservation
Division, Office of Protected Resources, National Marine Fisheries
Service, 1315 East-West Highway, Silver Spring, MD 20910. The mailbox
address for providing email comments is itp.fiorentino@noaa.gov.
Comments sent via email, including all attachments, must not exceed a
25-megabyte file size. NMFS is not responsible for comments sent to
addresses other than those provided here.
Instructions: All comments received are a part of the public record
and will generally be posted to http://www.nmfs.noaa.gov/pr/permits/incidental/ without change. All Personal Identifying Information (for
example, name, address, etc.) voluntarily submitted by the commenter
may be publicly accessible. Do not submit Confidential Business
Information or otherwise sensitive or protected information.
An electronic copy of the application may be obtained by writing to
the address specified above, telephoning the contact listed below (see
FOR FURTHER INFORMATION CONTACT), or visiting the Internet at: http://www.nmfs.noaa.gov/pr/permits/incidental/. Documents cited in this
notice may also be viewed, by appointment, during regular business
hours, at the aforementioned address.
The Navy is also preparing an Environmental Assessment (EA) in
accordance with the National Environmental Policy Act (NEPA), to
evaluate all components of the proposed Civilian Port Defense training
activities. NMFS intends to adopt the Navy's EA, if adequate and
appropriate. Currently, we believe that the adoption of the Navy's EA
will allow NMFS to meet its responsibilities under NEPA for the
issuance of an IHA to the Navy for Civilian Port Defense activities at
the Ports of Los Angeles and Long Beach Harbor. If necessary, however,
NMFS will supplement the existing analysis to ensure that we comply
with NEPA prior to the issuance of the final IHA.
FOR FURTHER INFORMATION CONTACT: John Fiorentino, Office of Protected
Resources, NMFS, (301) 427-8477.
SUPPLEMENTARY INFORMATION:
Background
Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.)
direct the Secretary of Commerce to allow, upon request, the
incidental, but not intentional, taking of small numbers of marine
mammals by U.S. citizens who engage in a specified activity (other than
commercial fishing) within a specified geographical region if certain
findings are made and either regulations are issued or, if the taking
is limited to harassment, a notice of a proposed authorization is
provided to the public for review.
An authorization for incidental takings shall be granted if NMFS
finds that the taking will have a negligible impact on the species or
stock(s), will not have an unmitigable adverse impact on the
availability of the species or stock(s) for subsistence uses (where
relevant), and if the permissible methods of taking and requirements
pertaining to the mitigation, monitoring and reporting of such takings
are set forth. NMFS has defined ``negligible impact'' in 50 CFR 216.103
as ``an impact resulting from the specified activity that cannot be
reasonably expected to, and is not reasonably likely to, adversely
affect the species or stock through effects on annual rates of
recruitment or survival.''
The National Defense Authorization Act of 2004 (NDAA) (Pub. L. 108-
136) removed the ``small numbers'' and ``specified geographical
region'' limitations indicated above and amended the definition of
``harassment'' as it applies to a ``military readiness activity'' to
read as follows (Section 3(18)(B) of the MMPA): (i) Any act that
injures or has the significant potential to injure a marine mammal or
marine mammal stock in the wild [Level A Harassment]; or (ii) Any act
that disturbs or is likely to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of natural behavioral patterns,
to a point where such behavioral patterns are abandoned or
significantly altered [Level B Harassment].
Except with respect to certain activities not pertinent here, the
MMPA defines ``harassment'' as: Any act of pursuit, torment, or
annoyance which (i) has the potential to injure a marine mammal or
marine mammal stock in the wild [Level A harassment]; or (ii) has the
potential to disturb a marine mammal or marine mammal stock in the wild
by causing disruption of behavioral patterns, including, but not
limited to, migration, breathing, nursing, breeding, feeding, or
sheltering [Level B harassment].
Summary of Request
On April 16, 2015, NMFS received an application from the Navy
requesting an IHA for the taking of marine mammals incidental to
Civilian Port Defense activities at the Ports of Los Angeles and Long
Beach, California from October through November, 2015.
The Study Area includes the waters within and near the Ports of Los
Angeles and Long Beach, California. Since the Ports of Los Angeles and
Long Beach are adjacent and are both encompassed within the larger
proposed action area (Study Area) they will be described collectively
as Los Angeles/Long Beach (see Figure 2-1 of the application for a map
of the Study Area). These activities are classified as military
readiness activities. Marine mammals present in the Study Area may be
exposed to sound from active acoustic sources (sonar). The Navy is
requesting authorization to take 7 marine mammal species by Level B
harassment (behavioral). No injurious takes (Level A harassment) of
marine mammals are predicted and, therefore, none are being authorized.
Description of the Specified Activity
Civilian Port Defense activities are naval mine warfare exercises
conducted in support of maritime homeland defense, per the Maritime
Operational Threat Response Plan. These activities are conducted in
conjunction with other federal agencies, principally the Department of
Homeland Security. The
[[Page 53659]]
three pillars of Mine Warfare include airborne (helicopter), surface
(ship and unmanned vehicles), and undersea (divers, marine mammal
systems, and unmanned vehicles), all of which are used in order to
ensure that strategic U.S. ports are cleared of mine threats. Civilian
Port Defense events are conducted in ports or major surrounding
waterways, within the shipping lanes, and seaward to the 300 feet (ft,
91 meters [m]) depth contour. The events employ the use of various mine
detection sensors, some of which utilize active acoustics for detection
of mines and mine-like objects in and around various ports. Assets used
during Civilian Port Defense training include up to four unmanned
underwater vehicles, marine mammal systems, up to two helicopters
operating (two to four hours) at altitudes as low as 75 to 100 ft (23
to 31 m), explosive ordnance disposal platoons, a Littoral Combat Ship
or Landing Dock Platform and AVENGER class ships. The AVENGER is a
surface mine countermeasure vessel specifically outfitted for mine
countermeasure capability. The proposed Civilian Port Defense
activities for Los Angeles/Long Beach include the use of up to 20
bottom placed non explosive mine training shapes. Mine shapes may be
retrieved by Navy divers, typically explosive ordnance disposal
personnel, and may be brought to beach side locations to ensure that
the neutralization measures are effective and the shapes are secured.
The final step to the beach side activity is the intelligence gathering
and identifying how the mine works, disassembling it or neutralizing
it. The entire training event takes place over multiple weeks utilizing
a variety of assets and scenarios. The following descriptions detail
the possible range of activities which could take place during a
Civilian Port Defense training event. This is all inclusive and many of
these activities are not included within the analysis of this specific
event. Mine detection including towed or hull mounted sources would be
the only portion of this event which we are proposing authorization.
Mine Detection Systems
Mine detection systems are used to locate, classify, and map
suspected mines (Figure 1-1 of the application). Once located, the
mines can either be neutralized or avoided. These systems are
specialized to either locate mines on the surface, in the water column,
or on the sea floor.
Towed or Hull-Mounted Mine Detection Systems. These
detection systems use acoustic and laser or video sensors to locate and
classify suspect mines. Helicopters, ships, and unmanned vehicles are
used with towed systems, which can rapidly assess large areas.
Unmanned/Remotely Operated Vehicles. These vehicles use
acoustic and video or lasers systems to locate and classify mines.
Unmanned/remotely operated vehicles provide mine warfare capabilities
in nearshore littoral areas, surf zones, ports, and channels.
Airborne Laser Mine Detection Systems. Airborne laser
detection systems work in concert with neutralization systems. The
detection system initially locates mines and a neutralization system is
then used to relocate and neutralize the mine.
Marine Mammal Systems. Navy personnel and Navy marine
mammals work together to detect specified underwater objects. The Navy
deploys trained bottlenose dolphins and California sea lions as part of
the marine mammal mine-hunting and object-recovery system.
Sonar systems to be used during Civilian Port Defense Mine
Detection training would include AN/SQQ-32, AN/SLQ-48, AN/AQS-24, and
handheld sonars (e.g., AN/PQS-2A). Of these sonar sources, only the AN/
SQQ-32 would require quantitative acoustic effects analysis, given its
source parameters. The AN/SQQ-32 is a high frequency (between 10 and
200 kilohertz [kHz]) sonar system; the specific source parameters of
the AN/SQQ-32 are classified. The AN/AQS-24, AN/SLQ-48 and handheld
sonars are considered de minimis sources, which are defined as sources
with low source levels, narrow beams, downward directed transmission,
short pulse lengths, frequencies above known hearing ranges, or some
combination of these factors (Department of the Navy 2013). De minimis
sources have been determined to not have potential impact to marine
mammals.
Mine Neutralization
Mine neutralization systems disrupt, disable, or detonate mines to
clear ports and shipping lanes. Mine neutralization systems can clear
individual mines or a large number of mines quickly. Two types of mine
neutralization could be conducted, mechanical minesweeping and
influence system minesweeping. Mechanical minesweeping consists of
cutting the tether of mines moored in the water column or other means
of physically releasing the mine. Moored mines cut loose by mechanical
sweeping must then be neutralized or rendered safe for subsequent
analysis. Influence minesweeping consists of simulating the magnetic,
electric, acoustic, seismic, or pressure signature of a ship so that
the mine detonates (no detonations would occur as part of the proposed
training activities). Mine neutralization is included here to present
the full spectrum of Civilian Port Defense Mine Warfare activities. The
mine neutralization component of the proposed Civilian Port Defense
training activities will not result in the incidental taking of marine
mammals.
Dates, Duration, and Geographic Region
Civilian Port Defense training activities are scheduled every year,
typically alternating between the east and west coasts of the United
States. Civilian Port Defense activities in 2015 are proposed to occur
on the U.S. west coast near Los Angeles/Long Beach, California.
Civilian Port Defense events are typically conducted in areas of ports
or major surrounding waterways and within the shipping lanes and
seaward to the 300 ft (91 m) depth contour.
Civilian Port Defense activities would occur at the Ports of Los
Angeles/Long Beach during October through November 2015 (Figure 2-1 of
the application). The training exercise would occur for a period of two
weeks in which active sonar would be utilized for two separate periods
of four day long events. The AN/SQQ-32 sonar could be active for up to
24 hours a day during these training events; however, the use of the
AN/SQQ-32 would not be continuously active during the four day long
period. Additional activities would occur during this time and are
analyzed within the Navy's Environmental Assessment for Civilian Port
Defense training activities. The Navy has determined there is potential
for take as defined under MMPA for military readiness activities.
Specifically take has potential to occur from utilization of active
sonar sources. This stressor is the only aspect of the proposed
training activities for which this IHA is being requested.
The Ports of Los Angeles and Long Beach combined represent the
busiest port along the U.S. West Coast and second busiest in the United
States. In 2012 and 2013, approximately 4,550 and 4,500 vessel calls,
respectively, for ships over 10,000 deadweight tons arrived at the
Ports of Los Angeles and Long Beach (Louttit and Chavez 2014; U.S.
Department of Transportation). This level of shipping would mean
approximately 9,000 large ship transits to and from these ports and
through the Study Area. By comparison, the next
[[Page 53660]]
nearest large regional port, Port of San Diego, only had 318 vessel
calls in 2012.
Description of Marine Mammals in the Area of the Specified Activity
Nineteen marine mammal species are known to occur in the study
area, including five mysticetes (baleen whales), nine odontocetes
(dolphins and toothed whales), and five pinnipeds (seals and sea
lions). Among these species are 31 stocks managed by NMFS. All species
were quantitatively analyzed in the Navy Acoustic Effects Model (NAEMO;
see Chapter 6.4 of the application for additional information on the
modeling process). After completing the modeling simulations, seven
species (each with a single stock) are estimated to potentially be
taken by harassment as defined by the MMPA, as it applies to military
readiness, during the proposed Civilian Port Defense activities due to
use of active sonar sources. Based on a variety of factors, including
source characterization, species presence, species hearing range,
duration of exposure, and impact thresholds for species that may be
present, the remainder of the species were not quantitatively predicted
to be exposed to or affected by active acoustic transmissions related
to the proposed activities that would result in harassment under the
MMPA and, therefore, are not discussed further. Other potential
stressors related to the proposed Civilian Port Defense activities
(e.g., vessel movement/noise, in water device use) would not result in
disruption or alteration of breeding, feeding, or nursing patterns that
that would rise to a level of significance under the MMPA. The seven
species with the potential to be taken by harassment during the
proposed training activities are presented in Table 1 and relevant
information on their status, behavior, life history, distribution,
abundance, and hearing and vocalization is presented in Chapter 4 of
the application. Further information on the general biology and ecology
of marine mammals is included in the Navy's EA. In addition, NMFS
publishes annual SARs for marine mammals, including stocks that occur
within the Study Area (http://www.nmfs.noaa.gov/pr/species/mammals;
Carretta et al., 2014; Allen and Angliss, 2014).
Table 1--Marine Mammal Species With Estimated Exposures Above Harassment Thresholds in the Study Area
----------------------------------------------------------------------------------------------------------------
Stock abundance
Species Stock \1\ (coefficient Occurrence, seasonality, and
of variance) duration in study area
----------------------------------------------------------------------------------------------------------------
Odontocetes
----------------------------------------------------------------------------------------------------------------
Long-beaked common dolphin (Delphinus California............. 107,016 (0.42) Common inshore of 820 ft
capensis). (250 m) isobath. Species
may be more abundant in
study area from May to
October.
Short-beaked common dolphin California, Oregon, 411,211 (0.21) Primary occurrence between
(Delphinus delphis). Washington. the coast and 300 nautical
miles (nm) from shore.
Prefers water depths
between 650 and 6,500 ft
(200 and 2,000 m).
Risso's dolphin (Grampus griseus).... California, Oregon, 6,272 (0.30) Frequently observed in
Washington. waters surrounding San
Clemente Island,
California. Occurs on the
shelf in the Southern
California Bight. Highest
abundance is in the cold
season.
Pacific white-sided dolphin California, Oregon, 26,930 (0.28) Occurs primarily in shelf
(Lagenorhynchus obilquidens). Washington. and slope waters of
California; spends more
time in California waters
in colder water months.
Bottlenose dolphin coastal (Tursiops Coastal California..... 323 (0.13) Small, limited population;
truncatus). found within 1,640 ft (500
m) of the shoreline 99
percent of the time and
within 820 ft (250 m) 90
percent of the time.
----------------------------------------------------------------------------------------------------------------
Pinnipeds
----------------------------------------------------------------------------------------------------------------
Harbor seal (Phoca vitulina)......... California............. \2\ 30,196 (0.157) Found in moderate numbers.
Concentrate around haul-
outs in the Channel
Islands.
California sea lion (Zalophus U.S.................... 296,750 Most common pinniped.
californianus). Primarily congregate around
the Channel Islands. Peak
abundance is from May to
August.
----------------------------------------------------------------------------------------------------------------
\1\ From: Carretta et al. (2014). U.S. Pacific Marine Mammal Stock Assessments, 2013.
\2\ NMFS' draft U.S. Pacific Marine Mammal Stock Assessments, 2014 is proposing a small revision to the
California stock of harbor seals from 30,196 to 30,968. No other proposed revisions are anticipated for these
species.
Marine Mammal Hearing and Vocalizations
Cetaceans have an auditory anatomy that follows the basic mammalian
pattern, with some changes to adapt to the demands of hearing
underwater. The typical mammalian ear is divided into an outer ear,
middle ear, and inner ear. The outer ear is separated from the inner
ear by a tympanic membrane, or eardrum. In terrestrial mammals, the
outer ear, eardrum, and middle ear transmit airborne sound to the inner
ear, where the sound waves are propagated through the cochlear fluid.
Since the impedance of water is close to that of the tissues of a
cetacean, the outer ear is not required to transduce sound energy as it
does when sound waves travel from air to fluid (inner ear). Sound waves
traveling through the inner ear cause the basilar membrane to vibrate.
Specialized cells, called hair cells, respond to the vibration and
produce nerve pulses that are transmitted to the central nervous
system. Acoustic energy causes the basilar membrane in the cochlea to
vibrate. Sensory cells at different positions along the basilar
membrane are excited by different frequencies of sound (Pickles, 1998).
Marine mammal vocalizations often extend both above and below the
range of human hearing; vocalizations with frequencies lower than 20 Hz
are labeled as infrasonic and those higher than 20 kHz as ultrasonic
(National
[[Page 53661]]
Research Council (NRC), 2003; Figure 4-1). Measured data on the hearing
abilities of cetaceans are sparse, particularly for the larger
cetaceans such as the baleen whales. The auditory thresholds of some of
the smaller odontocetes have been determined in captivity. It is
generally believed that cetaceans should at least be sensitive to the
frequencies of their own vocalizations. Comparisons of the anatomy of
cetacean inner ears and models of the structural properties and the
response to vibrations of the ear's components in different species
provide an indication of likely sensitivity to various sound
frequencies. The ears of small toothed whales are optimized for
receiving high-frequency sound, while baleen whale inner ears are best
in low to infrasonic frequencies (Ketten, 1992; 1997; 1998).
Baleen whale vocalizations are composed primarily of frequencies
below 1 kHz, and some contain fundamental frequencies as low as 16 Hz
(Watkins et al., 1987; Richardson et al., 1995; Rivers, 1997; Moore et
al., 1998; Stafford et al., 1999; Wartzok and Ketten, 1999) but can be
as high as 24 kHz (humpback whale; Au et al., 2006). Clark and Ellison
(2004) suggested that baleen whales use low-frequency sounds not only
for long-range communication, but also as a simple form of echo
ranging, using echoes to navigate and orient relative to physical
features of the ocean. Information on auditory function in baleen
whales is extremely lacking. Sensitivity to low-frequency sound by
baleen whales has been inferred from observed vocalization frequencies,
observed reactions to playback of sounds, and anatomical analyses of
the auditory system. Although there is apparently much variation, the
source levels of most baleen whale vocalizations lie in the range of
150-190 dB re 1 microPascal ([micro]Pa) at 1 m. Low-frequency
vocalizations made by baleen whales and their corresponding auditory
anatomy suggest that they have good low-frequency hearing (Ketten,
2000), although specific data on sensitivity, frequency or intensity
discrimination, or localization abilities are lacking. Marine mammals,
like all mammals, have typical U-shaped audiograms that begin with
relatively low sensitivity (high threshold) at some specified low
frequency with increased sensitivity (low threshold) to a species
specific optimum followed by a generally steep rise at higher
frequencies (high threshold) (Fay, 1988).
The toothed whales produce a wide variety of sounds, which include
species-specific broadband ``clicks'' with peak energy between 10 and
200 kHz, individually variable ``burst pulse'' click trains, and
constant frequency or frequency-modulated (FM) whistles ranging from 4
to 16 kHz (Wartzok and Ketten, 1999). The general consensus is that the
tonal vocalizations (whistles) produced by toothed whales play an
important role in maintaining contact between dispersed individuals,
while broadband clicks are used during echolocation (Wartzok and
Ketten, 1999). Burst pulses have also been strongly implicated in
communication, with some scientists suggesting that they play an
important role in agonistic encounters (McCowan and Reiss, 1995), while
others have proposed that they represent ``emotive'' signals in a
broader sense, possibly representing graded communication signals
(Herzing, 1996). Sperm whales, however, are known to produce only
clicks, which are used for both communication and echolocation
(Whitehead, 2003). Most of the energy of toothed whale social
vocalizations is concentrated near 10 kHz, with source levels for
whistles as high as 100 to 180 dB re 1 [micro]Pa at 1 m (Richardson et
al., 1995). No odontocete has been shown audiometrically to have acute
hearing (<80 dB re 1 [micro]Pa) below 500 Hz (DoN, 2001). Sperm whales
produce clicks, which may be used to echolocate (Mullins et al., 1988),
with a frequency range from less than 100 Hz to 30 kHz and source
levels up to 230 dB re 1 [micro]Pa 1 m or greater (Mohl et al., 2000).
Brief Background on Sound
An understanding of the basic properties of underwater sound is
necessary to comprehend many of the concepts and analyses presented in
this document. A summary is included below.
Sound is a wave of pressure variations propagating through a medium
(e.g., water). Pressure variations are created by compressing and
relaxing the medium. Sound measurements can be expressed in two forms:
intensity and pressure. Acoustic intensity is the average rate of
energy transmitted through a unit area in a specified direction and is
expressed in watts per square meter (W/m\2\). Acoustic intensity is
rarely measured directly, but rather from ratios of pressures; the
standard reference pressure for underwater sound is 1 [micro]Pa; for
airborne sound, the standard reference pressure is 20 [micro]Pa
(Richardson et al., 1995).
Acousticians have adopted a logarithmic scale for sound
intensities, which is denoted in decibels (dB). Decibel measurements
represent the ratio between a measured pressure value and a reference
pressure value (in this case 1 [micro]Pa or, for airborne sound, 20
[micro]Pa). The logarithmic nature of the scale means that each 10-dB
increase is a ten-fold increase in acoustic power (and a 20-dB increase
is then a 100-fold increase in power; and a 30-dB increase is a 1,000-
fold increase in power). A ten-fold increase in acoustic power does not
mean that the sound is perceived as being ten times louder, however.
Humans perceive a 10-dB increase in sound level as a doubling of
loudness, and a 10-dB decrease in sound level as a halving of loudness.
The term ``sound pressure level'' implies a decibel measure and a
reference pressure that is used as the denominator of the ratio.
Throughout this document, NMFS uses 1 [micro]Pa (denoted re:
1[micro]Pa) as a standard reference pressure unless noted otherwise.
It is important to note that decibel values underwater and decibel
values in air are not the same (different reference pressures and
densities/sound speeds between media) and should not be directly
compared. Because of the different densities of air and water and the
different decibel standards (i.e., reference pressures) in air and
water, a sound with the same level in air and in water would be
approximately 62 dB lower in air. Thus, a sound that measures 160 dB
(re 1 [micro]Pa) underwater would have the same approximate effective
level as a sound that is 98 dB (re 20 [micro]Pa) in air.
Sound frequency is measured in cycles per second, or Hertz
(abbreviated Hz), and is analogous to musical pitch; high-pitched
sounds contain high frequencies and low-pitched sounds contain low
frequencies. Natural sounds in the ocean span a huge range of
frequencies: from earthquake noise at 5 Hz to harbor porpoise clicks at
150,000 Hz (150 kHz). These sounds are so low or so high in pitch that
humans cannot even hear them; acousticians call these infrasonic
(typically below 20 Hz) and ultrasonic (typically above 20,000 Hz)
sounds, respectively. A single sound may be made up of many different
frequencies together. Sounds made up of only a small range of
frequencies are called ``narrowband'', and sounds with a broad range of
frequencies are called ``broadband''; explosives are an example of a
broadband sound source and active tactical sonars are an example of a
narrowband sound source.
When considering the influence of various kinds of sound on the
marine environment, it is necessary to understand that different kinds
of marine life are sensitive to different frequencies of sound. Current
data indicate that not all marine mammal species have equal hearing
capabilities
[[Page 53662]]
(Richardson et al., 1995; Southall et al., 1997; Wartzok and Ketten,
1999; Au and Hastings, 2008).
Southall et al. (2007) designated ``functional hearing groups'' for
marine mammals based on available behavioral data; audiograms derived
from auditory evoked potentials; anatomical modeling; and other data.
Southall et al. (2007) also estimated the lower and upper frequencies
of functional hearing for each group. However, animals are less
sensitive to sounds at the outer edges of their functional hearing
range and are more sensitive to a range of frequencies within the
middle of their functional hearing range. Note that direct measurements
of hearing sensitivity do not exist for all species of marine mammals,
including low-frequency cetaceans. The functional hearing groups and
the associated frequencies developed by Southall et al. (2007) were
revised by Finneran and Jenkins (2012) and have been further modified
by NOAA. Table 2 provides a summary of sound production and general
hearing capabilities for marine mammal species (note that values in
this table are not meant to reflect absolute possible maximum ranges,
rather they represent the best known ranges of each functional hearing
group). For purposes of the analysis in this document, marine mammals
are arranged into the following functional hearing groups based on
their generalized hearing sensitivities: High-frequency cetaceans, mid-
frequency cetaceans, low-frequency cetaceans (mysticetes), phocids
(true seals), otariids (sea lion and fur seals), and mustelids (sea
otters). A detailed discussion of the functional hearing groups can be
found in Southall et al. (2007) and Finneran and Jenkins (2012).
Table 2--Marine Mammal Functional Hearing Groups
------------------------------------------------------------------------
Functional hearing group Functional hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 25 kHz.
whales).
Mid-frequency (MF) cetaceans (dolphins, 150 Hz to 160 kHz.
toothed whales, beaked whales, bottlenose
whales).
High-frequency (HF) cetaceans (true 200 Hz to 180 kHz.
porpoises, Kogia, river dolphins,
cephalorhynchid, Lagenorhynchus cruciger
& L. australis).
Phocid pinnipeds (underwater) (true seals) 75 Hz to 100 kHz.
Otariid pinnipeds (underwater) (sea lions 100 Hz to 48 kHz.
and fur seals).
------------------------------------------------------------------------
Adapted and derived from Southall et al. (2007).
* Represents frequency band of hearing for entire group as a composite
(i.e., all species within the group), where individual species'
hearing ranges are typically not as broad. Functional hearing is
defined as the range of frequencies a group hears without
incorporating non-acoustic mechanisms (Wartzok and Ketten, 1999). This
is ~ 60 to ~ 70 dB above best hearing sensitivity (Southall et al.,
2007) for all functional hearing groups except LF cetaceans, where no
direct measurements on hearing are available. For LF cetaceans, the
lower range is based on recommendations from Southall et al., 2007 and
the upper range is based on information on inner ear anatomy and
vocalizations.
When sound travels (propagates) from its source, its loudness
decreases as the distance traveled by the sound increases. Thus, the
loudness of a sound at its source is higher than the loudness of that
same sound a kilometer away. Acousticians often refer to the loudness
of a sound at its source (typically referenced to one meter from the
source) as the source level and the loudness of sound elsewhere as the
received level (i.e., typically the receiver). For example, a humpback
whale 3 km from a device that has a source level of 230 dB may only be
exposed to sound that is 160 dB loud, depending on how the sound
travels through water (e.g., spherical spreading [3 dB reduction with
doubling of distance] was used in this example). As a result, it is
important to understand the difference between source levels and
received levels when discussing the loudness of sound in the ocean or
its impacts on the marine environment.
As sound travels from a source, its propagation in water is
influenced by various physical characteristics, including water
temperature, depth, salinity, and surface and bottom properties that
cause refraction, reflection, absorption, and scattering of sound
waves. Oceans are not homogeneous and the contribution of each of these
individual factors is extremely complex and interrelated. The physical
characteristics that determine the sound's speed through the water will
change with depth, season, geographic location, and with time of day
(as a result, in actual active sonar operations, crews will measure
oceanic conditions, such as sea water temperature and depth, to
calibrate models that determine the path the sonar signal will take as
it travels through the ocean and how strong the sound signal will be at
a given range along a particular transmission path). As sound travels
through the ocean, the intensity associated with the wavefront
diminishes, or attenuates. This decrease in intensity is referred to as
propagation loss, also commonly called transmission loss.
Metrics Used in This Document
This section includes a brief explanation of the two sound
measurements (sound pressure level (SPL) and sound exposure level
(SEL)) frequently used to describe sound levels in the discussions of
acoustic effects in this document.
Sound pressure level (SPL)--Sound pressure is the sound force per
unit area, and is usually measured in micropascals ([micro]Pa), where 1
Pa is the pressure resulting from a force of one newton exerted over an
area of one square meter. SPL is expressed as the ratio of a measured
sound pressure and a reference level.
SPL (in dB) = 20 log (pressure/reference pressure)
The commonly used reference pressure level in underwater acoustics
is 1 [micro]Pa, and the units for SPLs are dB re: 1 [micro]Pa. SPL is
an instantaneous pressure measurement and can be expressed as the peak,
the peak-peak, or the root mean square (rms). Root mean square
pressure, which is the square root of the arithmetic average of the
squared instantaneous pressure values, is typically used in discussions
of the effects of sounds on vertebrates and all references to SPL in
this document refer to the root mean square. SPL does not take the
duration of exposure into account. SPL is the applicable metric used in
the risk continuum, which is used to estimate behavioral harassment
takes (see Level B Harassment Risk Function (Behavioral Harassment)
Section).
Sound exposure level (SEL)--SEL is an energy metric that integrates
the squared instantaneous sound pressure over a stated time interval.
The units for SEL are dB re: 1 [micro]Pa\2\-s. Below is a simplified
formula for SEL.
SEL = SPL + 10 log (duration in seconds)
As applied to active sonar, the SEL includes both the SPL of a
sonar ping
[[Page 53663]]
and the total duration. Longer duration pings and/or pings with higher
SPLs will have a higher SEL. If an animal is exposed to multiple pings,
the SEL in each individual ping is summed to calculate the cumulative
SEL. The cumulative SEL depends on the SPL, duration, and number of
pings received. The thresholds that NMFS uses to indicate at what
received level the onset of temporary threshold shift (TTS) and
permanent threshold shift (PTS) in hearing are likely to occur are
expressed as cumulative SEL.
Potential Effects of the Specified Activity on Marine Mammals
The Navy has requested authorization for the take of marine mammals
that may occur incidental to Civilian Port Defense training activities
in the Study Area. The Navy has analyzed potential impacts to marine
mammals from non-impulsive sound sources.
Other potential impacts to marine mammals from training activities
in the Study Area were analyzed in the Navy's EA, and determined to be
unlikely to result in marine mammal harassment. Therefore, the Navy has
not requested authorization for take of marine mammals that might occur
incidental to other components of its proposed activities. In this
document, NMFS analyzes the potential effects on marine mammals from
exposure to non-impulsive sound sources (active sonar).
For the purpose of MMPA authorizations, NMFS' effects assessments
serve four primary purposes: (1) To prescribe the permissible methods
of taking (i.e., Level B harassment (behavioral harassment), Level A
harassment (injury), or mortality, including an identification of the
number and types of take that could occur by harassment or mortality)
and to prescribe other means of effecting the least practicable adverse
impact on such species or stock and its habitat (i.e., mitigation); (2)
to determine whether the specified activity would have a negligible
impact on the affected species or stocks of marine mammals (based on
the likelihood that the activity would adversely affect the species or
stock through effects on annual rates of recruitment or survival); (3)
to determine whether the specified activity would have an unmitigable
adverse impact on the availability of the species or stock(s) for
subsistence uses; and (4) to prescribe requirements pertaining to
monitoring and reporting.
More specifically, for activities involving non-impulsive sources
(active sonar), NMFS' analysis will identify the probability of lethal
responses, physical trauma, sensory impairment (permanent and temporary
threshold shifts and acoustic masking), physiological responses
(particular stress responses), behavioral disturbance (that rises to
the level of harassment), and social responses (effects to social
relationships) that would be classified as a take and whether such take
would have a negligible impact on such species or stocks. This section
focuses qualitatively on the different ways that non-impulsive sources
may affect marine mammals (some of which NMFS would not classify as
harassment). Then, in the Estimated Take of Marine Mammals section, the
potential effects to marine mammals from non-impulsive sources will be
related to the MMPA definitions of Level B harassment, and we will
attempt to quantify those effects.
Non-Impulsive Sources
Direct Physiological Effects
Based on the literature, there are two basic ways that non-
impulsive sources might directly result in physical trauma or damage:
Noise-induced loss of hearing sensitivity (more commonly-called
``threshold shift'') and acoustically mediated bubble growth.
Threshold Shift (noise-induced loss of hearing)--When animals
exhibit reduced hearing sensitivity (i.e., sounds must be louder for an
animal to detect them) following exposure to an intense sound or sound
for long duration, it is referred to as a noise-induced threshold shift
(TS). An animal can experience temporary threshold shift (TTS) or
permanent threshold shift (PTS). TTS can last from minutes or hours to
days (i.e., there is complete recovery), can occur in specific
frequency ranges (i.e., an animal might only have a temporary loss of
hearing sensitivity between the frequencies of 1 and 10 kHz), and can
be of varying amounts (for example, an animal's hearing sensitivity
might be reduced initially by only 6 dB or reduced by 30 dB). PTS is
permanent, but some recovery is possible. PTS can also occur in a
specific frequency range and amount as mentioned above for TTS.
The following physiological mechanisms are thought to play a role
in inducing auditory TS: Effects to sensory hair cells in the inner ear
that reduce their sensitivity, modification of the chemical environment
within the sensory cells, residual muscular activity in the middle ear,
displacement of certain inner ear membranes, increased blood flow, and
post-stimulatory reduction in both efferent and sensory neural output
(Southall et al., 2007). The amplitude, duration, frequency, temporal
pattern, and energy distribution of sound exposure all can affect the
amount of associated TS and the frequency range in which it occurs. As
amplitude and duration of sound exposure increase, so, generally, does
the amount of TS, along with the recovery time. For intermittent
sounds, less TS could occur than compared to a continuous exposure with
the same energy (some recovery could occur between intermittent
exposures depending on the duty cycle between sounds) (Kryter et al.,
1966; Ward, 1997). For example, one short but loud (higher SPL) sound
exposure may induce the same impairment as one longer but softer sound,
which in turn may cause more impairment than a series of several
intermittent softer sounds with the same total energy (Ward, 1997).
Additionally, though TTS is temporary, prolonged exposure to sounds
strong enough to elicit TTS, or shorter-term exposure to sound levels
well above the TTS threshold, can cause PTS, at least in terrestrial
mammals (Kryter, 1985). Although in the case of mid- and high-frequency
active sonar (MFAS/HFAS), animals are not expected to be exposed to
levels high enough or durations long enough to result in PTS.
PTS is considered auditory injury (Southall et al., 2007).
Irreparable damage to the inner or outer cochlear hair cells may cause
PTS; however, other mechanisms are also involved, such as exceeding the
elastic limits of certain tissues and membranes in the middle and inner
ears and resultant changes in the chemical composition of the inner ear
fluids (Southall et al., 2007).
Although the published body of scientific literature contains
numerous theoretical studies and discussion papers on hearing
impairments that can occur with exposure to a loud sound, only a few
studies provide empirical information on the levels at which noise-
induced loss in hearing sensitivity occurs in nonhuman animals. For
marine mammals, published data are limited to the captive bottlenose
dolphin, beluga, harbor porpoise, and Yangtze finless porpoise
(Finneran et al., 2000, 2002b, 2003, 2005a, 2007, 2010a, 2010b;
Finneran and Schlundt, 2010; Lucke et al., 2009; Mooney et al., 2009a,
2009b; Popov et al., 2011a, 2011b; Kastelein et al., 2012a; Schlundt et
al., 2000; Nachtigall et al., 2003, 2004). For pinnipeds in water, data
are limited to measurements of TTS in harbor seals, an elephant seal,
and California sea lions (Kastak et al., 1999, 2005; Kastelein et al.,
2012b).
[[Page 53664]]
Marine mammal hearing plays a critical role in communication with
conspecifics, and interpretation of environmental cues for purposes
such as predator avoidance and prey capture. Depending on the degree
(elevation of threshold in dB), duration (i.e., recovery time), and
frequency range of TTS, and the context in which it is experienced, TTS
can have effects on marine mammals ranging from discountable to serious
(similar to those discussed in auditory masking, below). For example, a
marine mammal may be able to readily compensate for a brief, relatively
small amount of TTS in a non-critical frequency range that occurs
during a time where ambient noise is lower and there are not as many
competing sounds present. Alternatively, a larger amount and longer
duration of TTS sustained during time when communication is critical
for successful mother/calf interactions could have more serious
impacts. Also, depending on the degree and frequency range, the effects
of PTS on an animal could range in severity, although it is considered
generally more serious because it is a permanent condition. Of note,
reduced hearing sensitivity as a simple function of aging has been
observed in marine mammals, as well as humans and other taxa (Southall
et al., 2007), so one can infer that strategies exist for coping with
this condition to some degree, though likely not without cost.
Acoustically Mediated Bubble Growth--One theoretical cause of
injury to marine mammals is rectified diffusion (Crum and Mao, 1996),
the process of increasing the size of a bubble by exposing it to a
sound field. This process could be facilitated if the environment in
which the ensonified bubbles exist is supersaturated with gas.
Repetitive diving by marine mammals can cause the blood and some
tissues to accumulate gas to a greater degree than is supported by the
surrounding environmental pressure (Ridgway and Howard, 1979). The
deeper and longer dives of some marine mammals (for example, beaked
whales) are theoretically predicted to induce greater supersaturation
(Houser et al., 2001b). If rectified diffusion were possible in marine
mammals exposed to high-level sound, conditions of tissue
supersaturation could theoretically speed the rate and increase the
size of bubble growth. Subsequent effects due to tissue trauma and
emboli would presumably mirror those observed in humans suffering from
decompression sickness.
It is unlikely that the short duration of sonar pings would be long
enough to drive bubble growth to any substantial size, if such a
phenomenon occurs. However, an alternative but related hypothesis has
also been suggested: Stable bubbles could be destabilized by high-level
sound exposures such that bubble growth then occurs through static
diffusion of gas out of the tissues. In such a scenario the marine
mammal would need to be in a gas-supersaturated state for a long enough
period of time for bubbles to become of a problematic size. Recent
research with ex vivo supersaturated bovine tissues suggested that, for
a 37 kHz signal, a sound exposure of approximately 215 dB referenced to
(re) 1 [mu]Pa would be required before microbubbles became destabilized
and grew (Crum et al., 2005). Assuming spherical spreading loss and a
nominal sonar source level of 235 dB re 1 [mu]Pa at 1 m, a whale would
need to be within 10 m (33 ft.) of the sonar dome to be exposed to such
sound levels. Furthermore, tissues in the study were supersaturated by
exposing them to pressures of 400-700 kilopascals for periods of hours
and then releasing them to ambient pressures. Assuming the
equilibration of gases with the tissues occurred when the tissues were
exposed to the high pressures, levels of supersaturation in the tissues
could have been as high as 400-700 percent. These levels of tissue
supersaturation are substantially higher than model predictions for
marine mammals (Houser et al., 2001; Saunders et al., 2008). It is
improbable that this mechanism is responsible for stranding events or
traumas associated with beaked whale strandings. Both the degree of
supersaturation and exposure levels observed to cause microbubble
destabilization are unlikely to occur, either alone or in concert.
Yet another hypothesis (decompression sickness) has speculated that
rapid ascent to the surface following exposure to a startling sound
might produce tissue gas saturation sufficient for the evolution of
nitrogen bubbles (Jepson et al., 2003; Fernandez et al., 2005;
Fern[aacute]ndez et al., 2012). In this scenario, the rate of ascent
would need to be sufficiently rapid to compromise behavioral or
physiological protections against nitrogen bubble formation.
Alternatively, Tyack et al. (2006) studied the deep diving behavior of
beaked whales and concluded that: ``Using current models of breath-hold
diving, we infer that their natural diving behavior is inconsistent
with known problems of acute nitrogen supersaturation and embolism.''
Collectively, these hypotheses can be referred to as ``hypotheses of
acoustically mediated bubble growth.''
Although theoretical predictions suggest the possibility for
acoustically mediated bubble growth, there is considerable disagreement
among scientists as to its likelihood (Piantadosi and Thalmann, 2004;
Evans and Miller, 2003). Crum and Mao (1996) hypothesized that received
levels would have to exceed 190 dB in order for there to be the
possibility of significant bubble growth due to supersaturation of
gases in the blood (i.e., rectified diffusion). More recent work
conducted by Crum et al. (2005) demonstrated the possibility of
rectified diffusion for short duration signals, but at SELs and tissue
saturation levels that are highly improbable to occur in diving marine
mammals. To date, energy levels (ELs) predicted to cause in vivo bubble
formation within diving cetaceans have not been evaluated (NOAA,
2002b). Although it has been argued that traumas from some recent
beaked whale strandings are consistent with gas emboli and bubble-
induced tissue separations (Jepson et al., 2003), there is no
conclusive evidence of this. However, Jepson et al. (2003, 2005) and
Fernandez et al. (2004, 2005, 2012) concluded that in vivo bubble
formation, which may be exacerbated by deep, long-duration, repetitive
dives may explain why beaked whales appear to be particularly
vulnerable to sonar exposures. Further investigation is needed to
further assess the potential validity of these hypotheses.
Acoustic Masking
Marine mammals use acoustic signals for a variety of purposes,
which differ among species, but include communication between
individuals, navigation, foraging, reproduction, and learning about
their environment (Erbe and Farmer, 2000; Tyack, 2000). Masking, or
auditory interference, generally occurs when sounds in the environment
are louder than and of a similar frequency to, auditory signals an
animal is trying to receive. Masking is a phenomenon that affects
animals that are trying to receive acoustic information about their
environment, including sounds from other members of their species,
predators, prey, and sounds that allow them to orient in their
environment. Masking these acoustic signals can disturb the behavior of
individual animals, groups of animals, or entire populations.
The extent of the masking interference depends on the spectral,
temporal, and spatial relationships between the signals an animal is
trying to receive and the masking noise, in addition to other factors.
In humans, significant masking of tonal signals occurs as a result of
[[Page 53665]]
exposure to noise in a narrow band of similar frequencies. As the sound
level increases, though, the detection of frequencies above those of
the masking stimulus decreases also. This principle is expected to
apply to marine mammals as well because of common biomechanical
cochlear properties across taxa.
Richardson et al. (1995b) argued that the maximum radius of
influence of an industrial noise (including broadband low frequency
sound transmission) on a marine mammal is the distance from the source
to the point at which the noise can barely be heard. This range is
determined by either the hearing sensitivity of the animal or the
background noise level present. Industrial masking is most likely to
affect some species' ability to detect communication calls and natural
sounds (i.e., surf noise, prey noise, etc.; Richardson et al., 1995).
The echolocation calls of toothed whales are subject to masking by
high frequency sound. Human data indicate low-frequency sound can mask
high-frequency sounds (i.e., upward masking). Studies on captive
odontocetes by Au et al. (1974, 1985, 1993) indicate that some species
may use various processes to reduce masking effects (e.g., adjustments
in echolocation call intensity or frequency as a function of background
noise conditions). There is also evidence that the directional hearing
abilities of odontocetes are useful in reducing masking at the high-
frequencies these cetaceans use to echolocate, but not at the low-to-
moderate frequencies they use to communicate (Zaitseva et al., 1980). A
recent study by Nachtigall and Supin (2008) showed that false killer
whales adjust their hearing to compensate for ambient sounds and the
intensity of returning echolocation signals.
As mentioned previously, the functional hearing ranges of
odontocetes and pinnipeds underwater overlap the frequencies of the
high-frequency sonar source (i.e., AN/SQQ-32) used in the Navy's
training exercises. Additionally, species' vocal repertoires span
across the frequencies of the sonar source used by the Navy. The closer
the characteristics of the masking signal to the signal of interest,
the more likely masking is to occur. For hull-mounted and towed sonar
the pulse length and low duty cycle of the HFAS signal makes it less
likely that masking would occur as a result. Further, the frequency
band of the sonar is narrow, limiting the likelihood of auditory
masking.
Impaired Communication
In addition to making it more difficult for animals to perceive
acoustic cues in their environment, anthropogenic sound presents
separate challenges for animals that are vocalizing. When they
vocalize, animals are aware of environmental conditions that affect the
``active space'' of their vocalizations, which is the maximum area
within which their vocalizations can be detected before it drops to the
level of ambient noise (Brenowitz, 2004; Brumm et al., 2004; Lohr et
al., 2003). Animals are also aware of environmental conditions that
affect whether listeners can discriminate and recognize their
vocalizations from other sounds, which is more important than simply
detecting that a vocalization is occurring (Brenowitz, 1982; Brumm et
al., 2004; Dooling, 2004, Marten and Marler, 1977; Patricelli et al.,
2006). Most animals that vocalize have evolved with an ability to make
adjustments to their vocalizations to increase the signal-to-noise
ratio, active space, and recognizability/distinguishability of their
vocalizations in the face of temporary changes in background noise
(Brumm et al., 2004; Patricelli et al., 2006). Vocalizing animals can
make adjustments to vocalization characteristics such as the frequency
structure, amplitude, temporal structure, and temporal delivery.
Many animals will combine several of these strategies to compensate
for high levels of background noise. Anthropogenic sounds that reduce
the signal-to-noise ratio of animal vocalizations, increase the masked
auditory thresholds of animals listening for such vocalizations, or
reduce the active space of an animal's vocalizations impair
communication between animals. Most animals that vocalize have evolved
strategies to compensate for the effects of short-term or temporary
increases in background or ambient noise on their songs or calls.
Although the fitness consequences of these vocal adjustments remain
unknown, like most other trade-offs animals must make, some of these
strategies probably come at a cost (Patricelli et al., 2006). For
example, vocalizing more loudly in noisy environments may have
energetic costs that decrease the net benefits of vocal adjustment and
alter a bird's energy budget (Brumm, 2004; Wood and Yezerinac, 2006).
Shifting songs and calls to higher frequencies may also impose
energetic costs (Lambrechts, 1996).
Stress Responses
Classic stress responses begin when an animal's central nervous
system perceives a potential threat to its homeostasis. That perception
triggers stress responses regardless of whether a stimulus actually
threatens the animal; the mere perception of a threat is sufficient to
trigger a stress response (Moberg, 2000; Sapolsky et al., 2005; Seyle,
1950). Once an animal's central nervous system perceives a threat, it
mounts a biological response or defense that consists of a combination
of the four general biological defense responses: behavioral responses,
autonomic nervous system responses, neuroendocrine responses, or immune
responses.
In the case of many stressors, an animal's first and sometimes most
economical (in terms of biotic costs) response is behavioral avoidance
of the potential stressor or avoidance of continued exposure to a
stressor. An animal's second line of defense to stressors involves the
sympathetic part of the autonomic nervous system and the classical
``fight or flight'' response which includes the cardiovascular system,
the gastrointestinal system, the exocrine glands, and the adrenal
medulla to produce changes in heart rate, blood pressure, and
gastrointestinal activity that humans commonly associate with
``stress.'' These responses have a relatively short duration and may or
may not have significant long-term effect on an animal's welfare.
An animal's third line of defense to stressors involves its
neuroendocrine systems; the system that has received the most study has
been the hypothalamus-pituitary-adrenal system (also known as the HPA
axis in mammals or the hypothalamus-pituitary-interrenal axis in fish
and some reptiles). Unlike stress responses associated with the
autonomic nervous system, virtually all neuro-endocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction (Moberg, 1987; Rivier, 1995), altered
metabolism (Elasser et al., 2000), reduced immune competence (Blecha,
2000), and behavioral disturbance. Increases in the circulation of
glucocorticosteroids (cortisol, corticosterone, and aldosterone in
marine mammals; see Romano et al., 2004) have been equated with stress
for many years.
[[Page 53666]]
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and distress is the biotic cost
of the response. During a stress response, an animal uses glycogen
stores that can be quickly replenished once the stress is alleviated.
In such circumstances, the cost of the stress response would not pose a
risk to the animal's welfare. However, when an animal does not have
sufficient energy reserves to satisfy the energetic costs of a stress
response, energy resources must be diverted from other biotic function,
which impairs those functions that experience the diversion. For
example, when mounting a stress response diverts energy away from
growth in young animals, those animals may experience stunted growth.
When mounting a stress response diverts energy from a fetus, an
animal's reproductive success and its fitness will suffer. In these
cases, the animals will have entered a pre-pathological or pathological
state which is called ``distress'' (Seyle, 1950) or ``allostatic
loading'' (McEwen and Wingfield, 2003). This pathological state will
last until the animal replenishes its biotic reserves sufficient to
restore normal function. Note that these examples involved a long-term
(days or weeks) stress response exposure to stimuli.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses have also been documented
fairly well through controlled experiments; because this physiology
exists in every vertebrate that has been studied, it is not surprising
that stress responses and their costs have been documented in both
laboratory and free-living animals (for examples see, Holberton et al.,
1996; Hood et al., 1998; Jessop et al., 2003; Krausman et al., 2004;
Lankford et al., 2005; Reneerkens et al., 2002; Thompson and Hamer,
2000). Information has also been collected on the physiological
responses of marine mammals to exposure to anthropogenic sounds (Fair
and Becker, 2000; Romano et al., 2002; Wright et al., 2008). For
example, Rolland et al. (2012) found that noise reduction from reduced
ship traffic in the Bay of Fundy was associated with decreased stress
in North Atlantic right whales. In a conceptual model developed by the
Population Consequences of Acoustic Disturbance (PCAD) working group,
serum hormones were identified as possible indicators of behavioral
effects that are translated into altered rates of reproduction and
mortality. The Office of Naval Research hosted a workshop (Effects of
Stress on Marine Mammals Exposed to Sound) in 2009 that focused on this
very topic (ONR, 2009).
Studies of other marine animals and terrestrial animals would also
lead us to expect some marine mammals to experience physiological
stress responses and, perhaps, physiological responses that would be
classified as ``distress'' upon exposure to high frequency, mid-
frequency and low-frequency sounds. For example, Jansen (1998) reported
on the relationship between acoustic exposures and physiological
responses that are indicative of stress responses in humans (for
example, elevated respiration and increased heart rates). Jones (1998)
reported on reductions in human performance when faced with acute,
repetitive exposures to acoustic disturbance. Trimper et al. (1998)
reported on the physiological stress responses of osprey to low-level
aircraft noise while Krausman et al. (2004) reported on the auditory
and physiology stress responses of endangered Sonoran pronghorn to
military overflights. Smith et al. (2004a, 2004b), for example,
identified noise-induced physiological transient stress responses in
hearing-specialist fish (i.e., goldfish) that accompanied short- and
long-term hearing losses. Welch and Welch (1970) reported physiological
and behavioral stress responses that accompanied damage to the inner
ears of fish and several mammals.
Hearing is one of the primary senses marine mammals use to gather
information about their environment and to communicate with
conspecifics. Although empirical information on the relationship
between sensory impairment (TTS, PTS, and acoustic masking) on marine
mammals remains limited, it seems reasonable to assume that reducing an
animal's ability to gather information about its environment and to
communicate with other members of its species would be stressful for
animals that use hearing as their primary sensory mechanism. Therefore,
we assume that acoustic exposures sufficient to trigger onset PTS or
TTS would be accompanied by physiological stress responses because
terrestrial animals exhibit those responses under similar conditions
(NRC, 2003). More importantly, marine mammals might experience stress
responses at received levels lower than those necessary to trigger
onset TTS. Based on empirical studies of the time required to recover
from stress responses (Moberg, 2000), we also assume that stress
responses are likely to persist beyond the time interval required for
animals to recover from TTS and might result in pathological and pre-
pathological states that would be as significant as behavioral
responses to TTS.
Behavioral Disturbance
Behavioral responses to sound are highly variable and context-
specific. Many different variables can influence an animal's perception
of and response to (nature and magnitude) an acoustic event. An
animal's prior experience with a sound or sound source effects whether
it is less likely (habituation) or more likely (sensitization) to
respond to certain sounds in the future (animals can also be innately
pre-disposed to respond to certain sounds in certain ways) (Southall et
al., 2007). Related to the sound itself, the perceived nearness of the
sound, bearing of the sound (approaching vs. retreating), similarity of
a sound to biologically relevant sounds in the animal's environment
(i.e., calls of predators, prey, or conspecifics), and familiarity of
the sound may affect the way an animal responds to the sound (Southall
et al., 2007). Individuals (of different age, gender, reproductive
status, etc.) among most populations will have variable hearing
capabilities, and differing behavioral sensitivities to sounds that
will be affected by prior conditioning, experience, and current
activities of those individuals. Often, specific acoustic features of
the sound and contextual variables (i.e., proximity, duration, or
recurrence of the sound or the current behavior that the marine mammal
is engaged in or its prior experience), as well as entirely separate
factors such as the physical presence of a nearby vessel, may be more
relevant to the animal's response than the received level alone.
Exposure of marine mammals to sound sources can result in no
response or responses including, but not limited to: Increased
alertness; orientation or attraction to a sound source; vocal
modifications; cessation of feeding; cessation of social interaction;
alteration of movement or diving behavior; habitat abandonment
(temporary or permanent); and, in severe cases, panic, flight,
stampede, or stranding, potentially resulting in death (Southall et
al., 2007). A review of marine mammal responses to anthropogenic sound
was first conducted by Richardson and others in 1995. A more recent
review (Nowacek et al., 2007) addresses studies conducted since 1995
and focuses on observations where the received sound level of the
exposed marine mammal(s) was known or could be estimated. The following
sub-sections provide examples of behavioral responses that provide an
idea of the variability in behavioral
[[Page 53667]]
responses that would be expected given the differential sensitivities
of marine mammal species to sound and the wide range of potential
acoustic sources to which a marine mammal may be exposed. Estimates of
the types of behavioral responses that could occur for a given sound
exposure should be determined from the literature that is available for
each species, or extrapolated from closely related species when no
information exists.
Flight Response--A flight response is a dramatic change in normal
movement to a directed and rapid movement away from the perceived
location of a sound source. Relatively little information on flight
responses of marine mammals to anthropogenic signals exist, although
observations of flight responses to the presence of predators have
occurred (Connor and Heithaus, 1996). Flight responses have been
speculated as being a component of marine mammal strandings associated
with sonar activities (Evans and England, 2001).
Response to Predator--Evidence suggests that at least some marine
mammals have the ability to acoustically identify potential predators.
For example, harbor seals that reside in the coastal waters off British
Columbia are frequently targeted by certain groups of killer whales,
but not others. The seals discriminate between the calls of threatening
and non-threatening killer whales (Deecke et al., 2002), a capability
that should increase survivorship while reducing the energy required
for attending to and responding to all killer whale calls. The
occurrence of masking or hearing impairment provides a means by which
marine mammals may be prevented from responding to the acoustic cues
produced by their predators. Whether or not this is a possibility
depends on the duration of the masking/hearing impairment and the
likelihood of encountering a predator during the time that predator
cues are impeded.
Diving--Changes in dive behavior can vary widely. They may consist
of increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive. Variations in
dive behavior may reflect interruptions in biologically significant
activities (e.g., foraging) or they may be of little biological
significance. Variations in dive behavior may also expose an animal to
potentially harmful conditions (e.g., increasing the chance of ship-
strike) or may serve as an avoidance response that enhances
survivorship. The impact of a variation in diving resulting from an
acoustic exposure depends on what the animal is doing at the time of
the exposure and the type and magnitude of the response.
Nowacek et al. (2004) reported disruptions of dive behaviors in
foraging North Atlantic right whales when exposed to an alerting
stimulus, an action, they noted, that could lead to an increased
likelihood of ship strike. However, the whales did not respond to
playbacks of either right whale social sounds or vessel noise,
highlighting the importance of the sound characteristics in producing a
behavioral reaction. Conversely, Indo-Pacific humpback dolphins have
been observed to dive for longer periods of time in areas where vessels
were present and/or approaching (Ng and Leung, 2003). In both of these
studies, the influence of the sound exposure cannot be decoupled from
the physical presence of a surface vessel, thus complicating
interpretations of the relative contribution of each stimulus to the
response. Indeed, the presence of surface vessels, their approach, and
speed of approach, seemed to be significant factors in the response of
the Indo-Pacific humpback dolphins (Ng and Leung, 2003). Low frequency
signals of the Acoustic Thermometry of Ocean Climate (ATOC) sound
source were not found to affect dive times of humpback whales in
Hawaiian waters (Frankel and Clark, 2000) or to overtly affect elephant
seal dives (Costa et al., 2003). They did, however, produce subtle
effects that varied in direction and degree among the individual seals,
illustrating the equivocal nature of behavioral effects and consequent
difficulty in defining and predicting them.
Due to past incidents of beaked whale strandings associated with
sonar operations, feedback paths are provided between avoidance and
diving and indirect tissue effects. This feedback accounts for the
hypothesis that variations in diving behavior and/or avoidance
responses can possibly result in nitrogen tissue supersaturation and
nitrogen off-gassing, possibly to the point of deleterious vascular
bubble formation (Jepson et al., 2003). Although hypothetical,
discussions surrounding this potential process are controversial.
Foraging--Disruption of feeding behavior can be difficult to
correlate with anthropogenic sound exposure, so it is usually inferred
by observed displacement from known foraging areas, the appearance of
secondary indicators (e.g., bubble nets or sediment plumes), or changes
in dive behavior. Noise from seismic surveys was not found to impact
the feeding behavior in western grey whales off the coast of Russia
(Yazvenko et al., 2007) and sperm whales engaged in foraging dives did
not abandon dives when exposed to distant signatures of seismic airguns
(Madsen et al., 2006). However, Miller et al. (2009) reported buzz
rates (a proxy for feeding) 19 percent lower during exposure to distant
signatures of seismic airguns. Balaenopterid whales exposed to moderate
low-frequency signals similar to the ATOC sound source demonstrated no
variation in foraging activity (Croll et al., 2001), whereas five out
of six North Atlantic right whales exposed to an acoustic alarm
interrupted their foraging dives (Nowacek et al., 2004). Although the
received sound pressure levels were similar in the latter two studies,
the frequency, duration, and temporal pattern of signal presentation
were different. These factors, as well as differences in species
sensitivity, are likely contributing factors to the differential
response. Blue whales exposed to simulated mid-frequency sonar in the
Southern California Bight were less likely to produce low frequency
calls usually associated with feeding behavior (Melc[oacute]n et al.,
2012). It is not known whether the lower rates of calling actually
indicated a reduction in feeding behavior or social contact since the
study used data from remotely deployed, passive acoustic monitoring
buoys. In contrast, blue whales increased their likelihood of calling
when ship noise was present, and decreased their likelihood of calling
in the presence of explosive noise, although this result was not
statistically significant (Melc[oacute]n et al., 2012). Additionally,
the likelihood of an animal calling decreased with the increased
received level of mid-frequency sonar, beginning at a SPL of
approximately 110-120 dB re 1 [micro]Pa (Melc[oacute]n et al., 2012).
Preliminary results from the 2010-2011 field season of an ongoing
behavioral response study in Southern California waters indicated that,
in some cases and at low received levels, tagged blue whales responded
to mid-frequency sonar but that those responses were mild and there was
a quick return to their baseline activity (Southall et al., 2011). A
determination of whether foraging disruptions incur fitness
consequences will require information on or estimates of the energetic
requirements of the individuals and the relationship between prey
availability, foraging effort and success, and the life history stage
of the animal. Goldbogen et al., (2013) monitored behavioral responses
of tagged blue whales located in feeding areas when exposed simulated
MFA
[[Page 53668]]
sonar. Responses varied depending on behavioral context, with deep
feeding whales being more significantly affected (i.e., generalized
avoidance; cessation of feeding; increased swimming speeds; or directed
travel away from the source) compared to surface feeding individuals
that typically showed no change in behavior. Non-feeding whales also
seemed to be affected by exposure. The authors indicate that disruption
of feeding and displacement could impact individual fitness and health.
However, for this to be true, we would have to assume that an
individual whale could not compensate for this lost feeding opportunity
by either immediately feeding at another location, by feeding shortly
after cessation of acoustic exposure, or by feeding at a later time.
There is no indication this is the case, particularly since unconsumed
prey would likely still be available in the environment in most cases
following the cessation of acoustic exposure.
Breathing--Variations in respiration naturally vary with different
behaviors and variations in respiration rate as a function of acoustic
exposure can be expected to co-occur with other behavioral reactions,
such as a flight response or an alteration in diving. However,
respiration rates in and of themselves may be representative of
annoyance or an acute stress response. Mean exhalation rates of gray
whales at rest and while diving were found to be unaffected by seismic
surveys conducted adjacent to the whale feeding grounds (Gailey et al.,
2007). Studies with captive harbor porpoises showed increased
respiration rates upon introduction of acoustic alarms (Kastelein et
al., 2001; Kastelein et al., 2006a) and emissions for underwater data
transmission (Kastelein et al., 2005). However, exposure of the same
acoustic alarm to a striped dolphin under the same conditions did not
elicit a response (Kastelein et al., 2006a), again highlighting the
importance in understanding species differences in the tolerance of
underwater noise when determining the potential for impacts resulting
from anthropogenic sound exposure (Southall et al., 2007; Henderson et
al., 2014).
Social Relationships--Social interactions between mammals can be
affected by noise via the disruption of communication signals or by the
displacement of individuals. Disruption of social relationships
therefore depends on the disruption of other behaviors (e.g., caused
avoidance, masking, etc.) and no specific overview is provided here.
However, social disruptions must be considered in context of the
relationships that are affected. Long-term disruptions of mother/calf
pairs or mating displays have the potential to affect the growth and
survival or reproductive effort/success of individuals, respectively.
Vocalizations (also see Masking Section)--Vocal changes in response
to anthropogenic noise can occur across the repertoire of sound
production modes used by marine mammals, such as whistling,
echolocation click production, calling, and singing. Changes may result
in response to a need to compete with an increase in background noise
or may reflect an increased vigilance or startle response. For example,
in the presence of low-frequency active sonar, humpback whales have
been observed to increase the length of their ``songs'' (Miller et al.,
2000; Fristrup et al., 2003), possibly due to the overlap in
frequencies between the whale song and the low-frequency active sonar.
A similar compensatory effect for the presence of low-frequency vessel
noise has been suggested for right whales; right whales have been
observed to shift the frequency content of their calls upward while
reducing the rate of calling in areas of increased anthropogenic noise
(Parks et al., 2007). Killer whales off the northwestern coast of the
U.S. have been observed to increase the duration of primary calls once
a threshold in observing vessel density (e.g., whale watching) was
reached, which has been suggested as a response to increased masking
noise produced by the vessels (Foote et al., 2004; NOAA, 2014b). In
contrast, both sperm and pilot whales potentially ceased sound
production during the Heard Island feasibility test (Bowles et al.,
1994), although it cannot be absolutely determined whether the
inability to acoustically detect the animals was due to the cessation
of sound production or the displacement of animals from the area.
Avoidance--Avoidance is the displacement of an individual from an
area as a result of the presence of a sound. Richardson et al., (1995)
noted that avoidance reactions are the most obvious manifestations of
disturbance in marine mammals. It is qualitatively different from the
flight response, but also differs in the magnitude of the response
(i.e., directed movement, rate of travel, etc.). Oftentimes avoidance
is temporary, and animals return to the area once the noise has ceased.
Longer term displacement is possible, however, which can lead to
changes in abundance or distribution patterns of the species in the
affected region if they do not become acclimated to the presence of the
sound (Blackwell et al., 2004; Bejder et al., 2006; Teilmann et al.,
2006). Acute avoidance responses have been observed in captive
porpoises and pinnipeds exposed to a number of different sound sources
(Kastelein et al., 2001; Finneran et al., 2003; Kastelein et al.,
2006a; Kastelein et al., 2006b). Short-term avoidance of seismic
surveys, low frequency emissions, and acoustic deterrents have also
been noted in wild populations of odontocetes (Bowles et al., 1994;
Goold, 1996; 1998; Stone et al., 2000; Morton and Symonds, 2002) and to
some extent in mysticetes (Gailey et al., 2007), while longer term or
repetitive/chronic displacement for some dolphin groups and for
manatees has been suggested to be due to the presence of chronic vessel
noise (Haviland-Howell et al., 2007; Miksis-Olds et al., 2007).
Maybaum (1993) conducted sound playback experiments to assess the
effects of MFAS on humpback whales in Hawaiian waters. Specifically,
she exposed focal pods to sounds of a 3.3-kHz sonar pulse, a sonar
frequency sweep from 3.1 to 3.6 kHz, and a control (blank) tape while
monitoring behavior, movement, and underwater vocalizations. The two
types of sonar signals (which both contained mid- and low-frequency
components) differed in their effects on the humpback whales, but both
resulted in avoidance behavior. The whales responded to the pulse by
increasing their distance from the sound source and responded to the
frequency sweep by increasing their swimming speeds and track
linearity. In the Caribbean, sperm whales avoided exposure to mid-
frequency submarine sonar pulses, in the range of 1000 Hz to 10,000 Hz
(IWC 2005).
Kvadsheim et al., (2007) conducted a controlled exposure experiment
in which killer whales fitted with D-tags were exposed to mid-frequency
active sonar (Source A: a 1.0 second upsweep 209 dB @1-2 kHz every 10
seconds for 10 minutes; Source B: with a 1.0 second upsweep 197 dB @6-7
kHz every 10 seconds for 10 minutes). When exposed to Source A, a
tagged whale and the group it was traveling with did not appear to
avoid the source. When exposed to Source B, the tagged whales along
with other whales that had been carousel feeding, ceased feeding during
the approach of the sonar and moved rapidly away from the source. When
exposed to Source B, Kvadsheim and his co-workers reported that a
tagged killer whale seemed to try to avoid further exposure to the
sound field by the following behaviors: immediately swimming away
(horizontally) from the source of the sound; engaging in a series of
erratic and frequently deep dives that seemed to take it below the
sound field;
[[Page 53669]]
or swimming away while engaged in a series of erratic and frequently
deep dives. Although the sample sizes in this study are too small to
support statistical analysis, the behavioral responses of the orcas
were consistent with the results of other studies.
In 2007, the first in a series of behavioral response studies, a
collaboration by the Navy, NMFS, and other scientists showed one beaked
whale (Mesoplodon densirostris) responding to an MFAS playback. Tyack
et al. (2011) indicates that the playback began when the tagged beaked
whale was vocalizing at depth (at the deepest part of a typical feeding
dive), following a previous control with no sound exposure. The whale
appeared to stop clicking significantly earlier than usual, when
exposed to mid-frequency signals in the 130-140 dB (rms) received level
range. After a few more minutes of the playback, when the received
level reached a maximum of 140-150 dB, the whale ascended on the slow
side of normal ascent rates with a longer than normal ascent, at which
point the exposure was terminated. The results are from a single
experiment and a greater sample size is needed before robust and
definitive conclusions can be drawn.
Tyack et al. (2011) also indicates that Blainville's beaked whales
appear to be sensitive to noise at levels well below expected TTS (~160
dB re 1 [micro]Pa). This sensitivity is manifest by an adaptive
movement away from a sound source. This response was observed
irrespective of whether the signal transmitted was within the band
width of MFAS, which suggests that beaked whales may not respond to the
specific sound signatures. Instead, they may be sensitive to any pulsed
sound from a point source in this frequency range. The response to such
stimuli appears to involve maximizing the distance from the sound
source.
Stimpert et al. (2014) tagged a Baird's beaked whale, which was
subsequently exposed to simulated mid-frequency sonar. Changes in the
animal's dive behavior and locomotion were observed when received level
reached 127 dB re 1 [mu]Pa.
Results from a 2007-2008 study conducted near the Bahamas showed a
change in diving behavior of an adult Blainville's beaked whale to
playback of mid-frequency source and predator sounds (Boyd et al.,
2008; Southall et al. 2009; Tyack et al., 2011). Reaction to mid-
frequency sounds included premature cessation of clicking and
termination of a foraging dive, and a slower ascent rate to the
surface. Results from a similar behavioral response study in southern
California waters have been presented for the 2010-2011 field season
(Southall et al. 2011; DeRuiter et al., 2013b). DeRuiter et al. (2013b)
presented results from two Cuvier's beaked whales that were tagged and
exposed to simulated mid-frequency active sonar during the 2010 and
2011 field seasons of the southern California behavioral response
study. The 2011 whale was also incidentally exposed to mid-frequency
active sonar from a distant naval exercise. Received levels from the
mid-frequency active sonar signals from the controlled and incidental
exposures were calculated as 84-144 and 78-106 dB re 1 [micro]Pa root
mean square (rms), respectively. Both whales showed responses to the
controlled exposures, ranging from initial orientation changes to
avoidance responses characterized by energetic fluking and swimming
away from the source. However, the authors did not detect similar
responses to incidental exposure to distant naval sonar exercises at
comparable received levels, indicating that context of the exposures
(e.g., source proximity, controlled source ramp-up) may have been a
significant factor. Cuvier's beaked whale responses suggested
particular sensitivity to sound exposure as consistent with results for
Blainville's beaked whale. Similarly, beaked whales exposed to sonar
during British training exercises stopped foraging (DSTL, 2007), and
preliminary results of controlled playback of sonar may indicate
feeding/foraging disruption of killer whales and sperm whales (Miller
et al., 2011).
In the 2007-2008 Bahamas study, playback sounds of a potential
predator--a killer whale--resulted in a similar but more pronounced
reaction, which included longer inter-dive intervals and a sustained
straight-line departure of more than 20 km from the area. The authors
noted, however, that the magnified reaction to the predator sounds
could represent a cumulative effect of exposure to the two sound types
since killer whale playback began approximately 2 hours after mid-
frequency source playback. Pilot whales and killer whales off Norway
also exhibited horizontal avoidance of a transducer with outputs in the
mid-frequency range (signals in the 1-2 kHz and 6-7 kHz ranges) (Miller
et al., 2011). Additionally, separation of a calf from its group during
exposure to mid-frequency sonar playback was observed on one occasion
(Miller et al., 2011). In contrast, preliminary analyses suggest that
none of the pilot whales or false killer whales in the Bahamas showed
an avoidance response to controlled exposure playbacks (Southall et
al., 2009).
Through analysis of the behavioral response studies, a preliminary
overarching effect of greater sensitivity to all anthropogenic
exposures was seen in beaked whales compared to the other odontocetes
studied (Southall et al., 2009). Therefore, recent studies have focused
specifically on beaked whale responses to active sonar transmissions or
controlled exposure playback of simulated sonar on various military
ranges (Defence Science and Technology Laboratory, 2007; Claridge and
Durban, 2009; Moretti et al., 2009; McCarthy et al., 2011; Tyack et
al., 2011). In the Bahamas, Blainville's beaked whales located on the
range will move off-range during sonar use and return only after the
sonar transmissions have stopped, sometimes taking several days to do
so (Claridge and Durban 2009; Moretti et al., 2009; McCarthy et al.,
2011; Tyack et al., 2011). Moretti et al. (2014) used recordings from
seafloor-mounted hydrophones at the Atlantic Undersea Test and
Evaluation Center (AUTEC) to analyze the probability of Blainsville's
beaked whale dives before, during, and after Navy sonar exercises.
Orientation--A shift in an animal's resting state or an attentional
change via an orienting response represent behaviors that would be
considered mild disruptions if occurring alone. As previously
mentioned, the responses may co-occur with other behaviors; for
instance, an animal may initially orient toward a sound source, and
then move away from it. Thus, any orienting response should be
considered in context of other reactions that may occur.
Behavioral Responses
Southall et al. (2007) reports the results of the efforts of a
panel of experts in acoustic research from behavioral, physiological,
and physical disciplines that convened and reviewed the available
literature on marine mammal hearing and physiological and behavioral
responses to human-made sound with the goal of proposing exposure
criteria for certain effects. This peer-reviewed compilation of
literature is very valuable, though Southall et al. (2007) note that
not all data are equal, some have poor statistical power, insufficient
controls, and/or limited information on received levels, background
noise, and other potentially important contextual variables--such data
were reviewed and sometimes used for qualitative illustration but were
not included in the quantitative analysis for the criteria
recommendations. All of the
[[Page 53670]]
studies considered, however, contain an estimate of the received sound
level when the animal exhibited the indicated response.
In the Southall et al. (2007) publication, for the purposes of
analyzing responses of marine mammals to anthropogenic sound and
developing criteria, the authors differentiate between single pulse
sounds, multiple pulse sounds, and non-pulse sounds. MFAS/HFAS sonar is
considered a non-pulse sound. Southall et al. (2007) summarize the
studies associated with low-frequency, mid-frequency, and high-
frequency cetacean and pinniped responses to non-pulse sounds, based
strictly on received level, in Appendix C of their article
(incorporated by reference and summarized in the three paragraphs
below).
The studies that address responses of low-frequency cetaceans to
non-pulse sounds include data gathered in the field and related to
several types of sound sources (of varying similarity to MFAS/HFAS)
including: Vessel noise, drilling and machinery playback, low-frequency
M-sequences (sine wave with multiple phase reversals) playback,
tactical low-frequency active sonar playback, drill ships, Acoustic
Thermometry of Ocean Climate (ATOC) source, and non-pulse playbacks.
These studies generally indicate no (or very limited) responses to
received levels in the 90 to 120 dB re: 1 [micro]Pa range and an
increasing likelihood of avoidance and other behavioral effects in the
120 to 160 dB range. As mentioned earlier, though, contextual variables
play a very important role in the reported responses and the severity
of effects are not linear when compared to received level. Also, few of
the laboratory or field datasets had common conditions, behavioral
contexts or sound sources, so it is not surprising that responses
differ.
The studies that address responses of mid-frequency cetaceans to
non-pulse sounds include data gathered both in the field and the
laboratory and related to several different sound sources (of varying
similarity to MFAS/HFAS) including: pingers, drilling playbacks, ship
and ice-breaking noise, vessel noise, Acoustic Harassment Devices
(AHDs), Acoustic Deterrent Devices (ADDs), MFAS, and non-pulse bands
and tones. Southall et al. (2007) were unable to come to a clear
conclusion regarding the results of these studies. In some cases,
animals in the field showed significant responses to received levels
between 90 and 120 dB, while in other cases these responses were not
seen in the 120 to 150 dB range. The disparity in results was likely
due to contextual variation and the differences between the results in
the field and laboratory data (animals typically responded at lower
levels in the field).
The studies that address responses of high frequency cetaceans to
non-pulse sounds include data gathered both in the field and the
laboratory and related to several different sound sources (of varying
similarity to MFAS/HFAS) including: pingers, AHDs, and various
laboratory non-pulse sounds. All of these data were collected from
harbor porpoises. Southall et al. (2007) concluded that the existing
data indicate that harbor porpoises are likely sensitive to a wide
range of anthropogenic sounds at low received levels (~ 90 to 120 dB),
at least for initial exposures. All recorded exposures above 140 dB
induced profound and sustained avoidance behavior in wild harbor
porpoises (Southall et al., 2007). Rapid habituation was noted in some
but not all studies. There is no data to indicate whether other high
frequency cetaceans are as sensitive to anthropogenic sound as harbor
porpoises are.
The studies that address the responses of pinnipeds in water to
non-pulse sounds include data gathered both in the field and the
laboratory and related to several different sound sources (of varying
similarity to MFAS/HFAS) including: AHDs, ATOC, various non-pulse
sounds used in underwater data communication; underwater drilling, and
construction noise. Few studies exist with enough information to
include them in the analysis. The limited data suggested that exposures
to non-pulse sounds between 90 and 140 dB generally do not result in
strong behavioral responses in pinnipeds in water, but no data exist at
higher received levels.
Potential Effects of Behavioral Disturbance
The different ways that marine mammals respond to sound are
sometimes indicators of the ultimate effect that exposure to a given
stimulus will have on the well-being (survival, reproduction, etc.) of
an animal. There is limited marine mammal data quantitatively relating
the exposure of marine mammals to sound to effects on reproduction or
survival, though data exists for terrestrial species to which we can
draw comparisons for marine mammals.
Attention is the cognitive process of selectively concentrating on
one aspect of an animal's environment while ignoring other things
(Posner, 1994). Because animals (including humans) have limited
cognitive resources, there is a limit to how much sensory information
they can process at any time. The phenomenon called ``attentional
capture'' occurs when a stimulus (usually a stimulus that an animal is
not concentrating on or attending to) ``captures'' an animal's
attention. This shift in attention can occur consciously or
subconsciously (for example, when an animal hears sounds that it
associates with the approach of a predator) and the shift in attention
can be sudden (Dukas, 2002; van Rij, 2007). Once a stimulus has
captured an animal's attention, the animal can respond by ignoring the
stimulus, assuming a ``watch and wait'' posture, or treat the stimulus
as a disturbance and respond accordingly, which includes scanning for
the source of the stimulus or ``vigilance'' (Cowlishaw et al., 2004).
Vigilance is normally an adaptive behavior that helps animals
determine the presence or absence of predators, assess their distance
from conspecifics, or to attend cues from prey (Bednekoff and Lima,
1998; Treves, 2000). Despite those benefits, however, vigilance has a
cost of time; when animals focus their attention on specific
environmental cues, they are not attending to other activities such as
foraging. These costs have been documented best in foraging animals,
where vigilance has been shown to substantially reduce feeding rates
(Saino, 1994; Beauchamp and Livoreil, 1997; Fritz et al., 2002).
Animals will spend more time being vigilant, which may translate to
less time foraging or resting, when disturbance stimuli approach them
more directly, remain at closer distances, have a greater group size
(for example, multiple surface vessels), or when they co-occur with
times that an animal perceives increased risk (for example, when they
are giving birth or accompanied by a calf). Most of the published
literature, however, suggests that direct approaches will increase the
amount of time animals will dedicate to being vigilant. For example,
bighorn sheep and Dall's sheep dedicated more time being vigilant, and
less time resting or foraging, when aircraft made direct approaches
over them (Frid, 2001; Stockwell et al., 1991).
Several authors have established that long-term and intense
disturbance stimuli can cause population declines by reducing the body
condition of individuals that have been disturbed, followed by reduced
reproductive success, reduced survival, or both (Daan et al., 1996;
Madsen, 1994; White, 1983). For example, Madsen (1994) reported that
pink-footed geese in undisturbed habitat gained body mass and had about
a 46-percent reproductive
[[Page 53671]]
success rate compared with geese in disturbed habitat (being
consistently scared off the fields on which they were foraging) which
did not gain mass and had a 17-percent reproductive success rate.
Similar reductions in reproductive success have been reported for mule
deer disturbed by all-terrain vehicles (Yarmoloy et al., 1988), caribou
disturbed by seismic exploration blasts (Bradshaw et al., 1998),
caribou disturbed by low-elevation military jet-fights (Luick et al.,
1996), and caribou disturbed by low-elevation jet flights (Harrington
and Veitch, 1992). Similarly, a study of elk that were disturbed
experimentally by pedestrians concluded that the ratio of young to
mothers was inversely related to disturbance rate (Phillips and
Alldredge, 2000).
The primary mechanism by which increased vigilance and disturbance
appear to affect the fitness of individual animals is by disrupting an
animal's time budget and, as a result, reducing the time they might
spend foraging and resting (which increases an animal's activity rate
and energy demand). For example, a study of grizzly bears reported that
bears disturbed by hikers reduced their energy intake by an average of
12 kcal/minute (50.2 x 10\3\kJ/minute), and spent energy fleeing or
acting aggressively toward hikers (White et al., 1999). Alternately,
Ridgway et al. (2006) reported that increased vigilance in bottlenose
dolphins exposed to sound over a 5-day period did not cause any sleep
deprivation or stress effects such as changes in cortisol or
epinephrine levels.
Lusseau and Bejder (2007) present data from three long-term studies
illustrating the connections between disturbance from whale-watching
boats and population-level effects in cetaceans. In Sharks Bay
Australia, the abundance of bottlenose dolphins was compared within
adjacent control and tourism sites over three consecutive 4.5-year
periods of increasing tourism levels. Between the second and third time
periods, in which tourism doubled, dolphin abundance decreased by 15
percent in the tourism area and did not change significantly in the
control area. In Fiordland, New Zealand, two populations (Milford and
Doubtful Sounds) of bottlenose dolphins with tourism levels that
differed by a factor of seven were observed and significant increases
in travelling time and decreases in resting time were documented for
both. Consistent short-term avoidance strategies were observed in
response to tour boats until a threshold of disturbance was reached
(average 68 minutes between interactions), after which the response
switched to a longer term habitat displacement strategy. For one
population tourism only occurred in a part of the home range, however,
tourism occurred throughout the home range of the Doubtful Sound
population and once boat traffic increased beyond the 68-minute
threshold (resulting in abandonment of their home range/preferred
habitat), reproductive success drastically decreased (increased
stillbirths) and abundance decreased significantly (from 67 to 56
individuals in short period). Last, in a study of northern resident
killer whales off Vancouver Island, exposure to boat traffic was shown
to reduce foraging opportunities and increase traveling time. A simple
bioenergetics model was applied to show that the reduced foraging
opportunities equated to a decreased energy intake of 18 percent, while
the increased traveling incurred an increased energy output of 3-4
percent, which suggests that a management action based on avoiding
interference with foraging might be particularly effective.
On a related note, many animals perform vital functions, such as
feeding, resting, traveling, and socializing, on a diel cycle (24-hour
cycle). Substantive behavioral reactions to noise exposure (such as
disruption of critical life functions, displacement, or avoidance of
important habitat) are more likely to be significant if they last more
than one diel cycle or recur on subsequent days (Southall et al.,
2007). Consequently, a behavioral response lasting less than 1 day and
not recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multiple-day
substantive behavioral reactions and multiple-day anthropogenic
activities. For example, just because an at-sea exercise lasts for
multiple days does not necessarily mean that individual animals are
either exposed to that exercise for multiple days or, further, exposed
in a manner resulting in a sustained multiple day substantive
behavioral responses.
In order to understand how the effects of activities may or may not
impact stocks and populations of marine mammals, it is necessary to
understand not only what the likely disturbances are going to be, but
how those disturbances may affect the reproductive success and
survivorship of individuals, and then how those impacts to individuals
translate to population changes. Following on the earlier work of a
committee of the U.S. National Research Council (NRC, 2005), New et al.
(2014), in an effort termed the Potential Consequences of Disturbance
(PCoD), outline an updated conceptual model of the relationships
linking disturbance to changes in behavior and physiology, health,
vital rates, and population dynamics (below). As depicted, behavioral
and physiological changes can either have direct (acute) effects on
vital rates, such as when changes in habitat use or increased stress
levels raise the probability of mother-calf separation or predation, or
they can have indirect and long-term (chronic) effects on vital rates,
such as when changes in time/energy budgets or increased disease
susceptibility affect health, which then affects vital rates (New et
al., 2014).
In addition to outlining this general framework and compiling the
relevant literature that supports it, New et al. (2014) have chosen
four example species for which extensive long-term monitoring data
exist (southern elephant seals, North Atlantic right whales, Ziphidae
beaked whales, and bottlenose dolphins) and developed state-space
energetic models that can be used to effectively forecast longer-term,
population-level impacts from behavioral changes. While these are very
specific models with very specific data requirements that cannot yet be
applied broadly to project-specific risk assessments, they are a
critical first step.
Vessels
Commercial and Navy ship strikes of cetaceans can cause major
wounds, which may lead to the death of the animal. An animal at the
surface could be struck directly by a vessel, a surfacing animal could
hit the bottom of a vessel, or an animal just below the surface could
be cut by a vessel's propeller. The severity of injuries typically
depends on the size and speed of the vessel (Knowlton and Kraus, 2001;
Laist et al., 2001; Vanderlaan and Taggart, 2007).
Marine mammals react to vessels in a variety of ways. Some respond
negatively by retreating or engaging in antagonistic responses while
other animals ignore the stimulus altogether (Terhune and Verboom,
1999; Watkins, 1986). Silber et al. (2010) concludes that large whales
that are in close proximity to a vessel may not regard the vessel as a
threat, or may be involved in a vital activity (i.e., mating or
feeding) which may not allow them to have a proper avoidance response.
Cetacean species generally pay little attention to transiting vessel
traffic as it approaches, although they may engage in last minute
avoidance maneuvers (Laist et al., 2001). Baleen whale responses to
vessel
[[Page 53672]]
traffic range from avoidance maneuvers to disinterest in the presence
of vessels (Nowacek et al., 2007; Scheidat et al., 2004). Species of
delphinids can vary widely in their reaction to vessels. Many exhibit
mostly neutral behavior, but there are frequent instances of observed
avoidance behaviors (Hewitt, 1985; W[uuml]rsig et al., 1998). Many
species of odontocetes (e.g., bottlenose dolphin) are frequently
observed bow riding or jumping in the wake of a vessel (Norris and
Prescott, 1961; Ritter, 2002; Shane et al., 1986; W[uuml]rsig et al.,
1998).
The most vulnerable marine mammals are those that spend extended
periods of time at the surface in order to restore oxygen levels within
their tissues after deep dives (e.g., the sperm whale). In addition,
some baleen whales, such as the North Atlantic right whale, seem
generally unresponsive to vessel sound, making them more susceptible to
vessel collisions (Nowacek et al., 2004). These species are primarily
large, slow moving whales. Smaller marine mammals (e.g., bottlenose
dolphin) move quickly through the water column.
An examination of all known ship strikes from all shipping sources
(civilian and military) indicates vessel speed is a principal factor in
whether a vessel strike results in death (Knowlton and Kraus, 2001;
Laist et al., 2001; Jensen and Silber, 2003; Vanderlaan and Taggart,
2007). In assessing records in which vessel speed was known, Laist et
al. (2001) found a direct relationship between the occurrence of a
whale strike and the speed of the vessel involved in the collision. The
authors concluded that most deaths occurred when a vessel was traveling
in excess of 13 knots.
Jensen and Silber (2003) detailed 292 records of known or probable
ship strikes of all large whale species from 1975 to 2002. Of these,
vessel speed at the time of collision was reported for 58 cases. Of
these cases, 39 (or 67 percent) resulted in serious injury or death (19
of those resulted in serious injury as determined by blood in the
water, propeller gashes or severed tailstock, and fractured skull, jaw,
vertebrae, hemorrhaging, massive bruising or other injuries noted
during necropsy and 20 resulted in death). Operating speeds of vessels
that struck various species of large whales ranged from 2 to 51 knots.
The majority (79 percent) of these strikes occurred at speeds of 13
knots or greater. The average speed that resulted in serious injury or
death was 18.6 knots. Pace and Silber (2005) found that the probability
of death or serious injury increased rapidly with increasing vessel
speed. Specifically, the predicted probability of serious injury or
death increased from 45 to 75 percent as vessel speed increased from 10
to 14 knots, and exceeded 90 percent at 17 knots. Higher speeds during
collisions result in greater force of impact and also appear to
increase the chance of severe injuries or death. While modeling studies
have suggested that hydrodynamic forces pulling whales toward the
vessel hull increase with increasing speed (Clyne, 1999; Knowlton et
al., 1995), this is inconsistent with Silber et al. (2010), which
demonstrated that there is no such relationship (i.e., hydrodynamic
forces are independent of speed).
The Jensen and Silber (2003) report notes that the database
represents a minimum number of collisions, because the vast majority
probably goes undetected or unreported. In contrast, Navy vessels are
likely to detect any strike that does occur, and they are required to
report all ship strikes involving marine mammals. Overall, the
percentages of Navy traffic relative to overall large shipping traffic
are very small (on the order of 2 percent).
Other efforts have been undertaken to investigate the impact from
vessels (both whale-watching and general vessel traffic noise) and
demonstrated impacts do occur (Bain, 2002; Erbe, 2002; Lusseau, 2009;
Williams et al., 2006, 2009, 2011b, 2013, 2014a, 2014b; Noren et al.,
2009; Read et al., 2014; Rolland et al., 2012; Pirotta et al., 2015).
This body of research for the most part has investigated impacts
associated with the presence of chronic stressors, which differ
significantly from generally intermittent Navy training and testing
activities. For example, in an analysis of energy costs to killer
whales, Williams et al. (2009) suggested that whale-watching in the
Johnstone Strait resulted in lost feeding opportunities due to vessel
disturbance, which could carry higher costs than other measures of
behavioral change might suggest. Ayres et al. (2012) recently reported
on research in the Salish Sea involving the measurement of southern
resident killer whale fecal hormones to assess two potential threats to
the species recovery: Lack of prey (salmon) and impacts to behavior
from vessel traffic. Ayres et al. (2012) suggested that the lack of
prey overshadowed any population-level physiological impacts on
southern resident killer whales from vessel traffic.
The Navy's Draft EA for 2015 West Coast Civilian Port Defense
training activities fully addressed the potential impacts of vessel
movement on marine mammals in the Study Area. The Navy does not
anticipate vessel strikes to marine mammals within the Study Area, nor
were takes by injury or mortality resulting from vessel strike
predicted in the Navy's analysis. Vessel strikes within the Study Area
are highly unlikely due to the size, maneuverability, and speed of the
surface mine countermeasure vessel (the AVENGER class ship would
typically operate at speeds less than 10 knots (18 km/hour); the
generally low likelihood of occurrence of large whales within the Study
Area; the effectiveness of Navy lookouts; and the implementation of
mitigation measures described below. Therefore, takes by injury or
mortality resulting from vessel strikes are not authorized by NMFS in
this proposed incidental harassment authorization. However, the Navy
has proposed measures (see Proposed Mitigation) to mitigate potential
impacts to marine mammals from vessel strike and other physical
disturbance (towed in-water devices) during training activities in the
Study Area.
Marine Mammal Habitat
The primary source of potential marine mammal habitat impact is
acoustic exposures resulting from mine detection and mine
neutralization activities. However, the exposures do not constitute a
long-term physical alteration of the water column or bottom topography,
as the occurrences are of limited duration and intermittent in time.
Marine mammal habitat and prey species may be temporarily impacted
by acoustic sources associated with the proposed activities. The
potential for acoustic sources to impact marine mammal habitat or prey
species is discussed below.
Expected Effects on Habitat
The effects of the introduction of sound into the environment are
generally considered to have a lesser impact on marine mammal habitat
than the physical alteration of the habitat. Acoustic exposures are not
expected to result in long-term physical alteration of the water column
or bottom topography, as the occurrences are of limited duration and
intermittent in time. The proposed training activities will only occur
during a two week period, and no military expended material would be
left as a result of this event.
The ambient underwater noise level within active shipping areas of
Los Angeles/Long Beach has been estimated around 140 dB re 1 [mu]Pa
(Tetra Tech Inc., 2011). Existing ambient acoustic levels in non-
shipping areas around Terminal Island in the Port of Long Beach ranged
between 120 dB and 132 dB re 1 [mu]Pa (Tetra Tech Inc., 2011).
Additional
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vessel noise, aircraft noise, and underwater acoustics associated with
the proposed training activities have the potential to temporarily
increase the noise levels of the Study Area. However, with ambient
levels of noise being elevated, the additional vessel noise would
likely be masked by the existing environmental noise and marine species
would not be impacted by the sound of the vessels or aircraft, but
perhaps by the sight of an approaching vessel or the shadow of a
helicopter.
Noise generated from helicopters is transient in nature and
variable in intensity. Helicopter sounds contain dominant tones from
the rotors that are generally below 500 Hz. Helicopters often radiate
more sound forward than aft. The underwater noise produced is generally
brief when compared with the duration of audibility in the air. The
sound pressure level from an H-60 helicopter hovering at a 50 ft (15 m)
altitude would be approximately 125 dB re 1 [mu]Pa at 1 m below the
water surface, which is lower than the ambient sound that has been
estimated in and around the Ports of Los Angeles/Long Beach. Helicopter
flights associated with the proposed activities could occur at
altitudes as low as 75 to 100 ft (23 to 31 m), and typically last two
to four hours.
Mine warfare sonar employs high frequencies (above 10 kHz) that
attenuate rapidly in the water, thus producing only a small area of
potential auditory masking. Odontocetes and pinnipeds may experience
some limited masking at closer ranges as the frequency band of many
mine warfare sonar overlaps the hearing and vocalization abilities of
some odontocetes and pinnipeds; however, the frequency band of the
sonar is narrow, limiting the likelihood of auditory masking.
The proposed training activities are of limited duration and
dispersion of the activities in space and time reduce the potential for
disturbance from ship-generated noise, helicopter noise, and acoustic
transmissions from the proposed activities on marine mammals. The
relatively high level of ambient noise in and near the busy shipping
channels also reduces the potential for any impact on habitat from the
addition of the platforms associated with the proposed activities.
Effects on Marine Mammal Prey
Invertebrates--Marine invertebrates in the Study Area inhabit
coastal waters and benthic habitats, including salt marshes, kelp
forests, and soft sediments, canyons, and the continential shelf. The
diverse range of species include oysters, crabs, worms, ghost shrimp,
snails, sponges, sea fans, isopods, and stony corals (Chess and Hobson
1997; Dugan et al. 2000; Proctor et al. 1980).
Very little is known about sound detection and use of sound by
aquatic invertebrates (Montgomery et al. 2006; Popper et al. 2001).
Organisms may detect sound by sensing either the particle motion or
pressure component of sound, or both. Aquatic invertebrates probably do
not detect pressure since many are generally the same density as water
and few, if any, have air cavities that would function like the fish
swim bladder in responding to pressure (Popper et al. 2001). Many
marine invertebrates, however, have ciliated ``hair'' cells that may be
sensitive to water movements, such as those caused by currents or water
particle motion very close to a sound source (Mackie and Singla 2003).
These cilia may allow invertebrates to sense nearby prey or predators
or help with local navigation. Marine invertebrates may produce and use
sound in territorial behavior, to deter predators, to find a mate, and
to pursue courtship (Popper et al. 2001).
Both behavioral and auditory brainstem response studies suggest
that crustaceans may sense sounds up to 3 kHz, but best sensitivity is
likely below 200 Hz (Goodall et al. 1990; Lovell et al. 2005; Lovell et
al. 2006). Most cephalopods (e.g., octopus and squid) likely sense low-
frequency sound below 1,000 Hz, with best sensitivities at lower
frequencies (Mooney et al. 2010; Packard et al. 1990). A few
cephalopods may sense higher frequencies up to 1,500 Hz (Hu et al.
2009). Squid did not respond to toothed whale ultrasonic echolocation
clicks at sound pressure levels ranging from 199 to 226 dB re 1
microPascal peak-to-peak, likely because these clicks were outside of
squid hearing range (Wilson et al. 2007). However, squid exhibited
alarm responses when exposed to broadband sound from an approaching
seismic airgun with received levels exceeding 145 to 150 dB re 1
microPascal root mean square (McCauley et al. 2000).
It is expected that most marine invertebrates would not sense high-
frequency sonar associated with the proposed activities. Most marine
invertebrates would not be close enough to active sonar systems to
potentially experience impacts to sensory structures. Any marine
invertebrate capable of sensing sound may alter its behavior if exposed
to sonar. Although acoustic transmissions produced during the proposed
activities may briefly impact individuals, intermittent exposures to
sonar are not expected to impact survival, growth, recruitment, or
reproduction of widespread marine invertebrate populations.
Fish--The portion of the California Bight in the vicinity of the
Study Area is a transitional zone between cold and warm water masses,
geographically separated by Point Conception, and is highly productive
(Leet et al. 2001). The cold-water of the California Bight is rich in
microscopic plankton (diatoms, krill, and other organisms), which form
the base of the food chain in the Study Area. Small coastal pelagic
fishes depend on this plankton and in turn are fed on by larger species
(such as highly migratory species). The high fish diversity found in
the Study Area occurs for several reasons: (1) The ranges of many
temperate and tropical species extend into Southern California, (2) the
area has complex bottom features and physical oceanographic features
that include several water masses and a changeable marine climate
offshore (Allen et al. 2006; Horn and Allen 1978), and (3) the islands
and coastal areas provide a diversity of habitats that include soft
bottom, rocky reefs, kelp beds, and estuaries, bays, and lagoons.
All fish have two sensory systems to detect sound in the water: The
inner ear, which functions very much like the inner ear in other
vertebrates, and the lateral line, which consists of a series of
receptors along the fish's body (Popper 2008). The inner ear generally
detects relatively higher-frequency sounds, while the lateral line
detects water motion at low frequencies (below a few hundred Hz)
(Hastings and Popper 2005). Although hearing capability data only exist
for fewer than 100 of the 32,000 fish species, current data suggest
that most species of fish detect sounds from 50 to 1,000 Hz, with few
fish hearing sounds above 4 kHz (Popper 2008). It is believed that most
fish have their best hearing sensitivity from 100 to 400 Hz (Popper
2003). Additionally, some clupeids (shad in the subfamily Alosinae)
possess ultrasonic hearing (i.e., able to detect sounds above 100 kHz)
(Astrup 1999). Permanent hearing loss, or PTS, has not been documented
in fish. The sensory hair cells of the inner ear in fish can regenerate
after they are damaged, unlike in mammals where sensory hair cells loss
is permanent (Lombarte et al. 1993; Smith et al. 2006). As a
consequence, any hearing loss in fish may be as temporary as the
timeframe required to repair or replace the sensory cells that were
damaged or destroyed (Smith et al. 2006).
Potential direct injuries from acoustic transmissions are unlikely
because of the relatively lower peak pressures and
[[Page 53674]]
slower rise times than potentially injurious sources such as
explosives. Acoustic sources also lack the strong shock waves
associated with an explosion. Therefore, direct injury is not likely to
occur from exposure to sonar. Only a few fish species are able to
detect high-frequency sonar and could have behavioral reactions or
experience auditory masking during these activities. These effects are
expected to be transient and long-term consequences for the population
are not expected. Hearing specialists are not expected to be within the
Study Area. If hearing specialists were present, they would have to in
close vicinity to the source to experience effects from the acoustic
transmission. While a large number of fish species may be able to
detect low-frequency sonar, some mid-frequency sonar and other active
acoustic sources, low-frequency and mid-frequency acoustic sources are
not planned as part of the proposed activities. Overall effects to fish
from active sonar sources would be localized, temporary and infrequent.
Based on the detailed review within the Navy's EA for 2015 Civilian
Port Defense training activities and the discussion above, there would
be no effects to marine mammals resulting from loss or modification of
marine mammal habitat or prey species related to the proposed
activities.
Marine Mammal Avoidance
Marine mammals may be temporarily displaced from areas where Navy
Civilian Port Defense training occurring, but the area should be
utilized again after the activities have ceased. Avoidance of an area
can help the animal avoid further acoustic effects by avoiding or
reducing further exposure. The intermittent or short duration of
training activities should prevent animals from being exposed to
stressors on a continuous basis. In areas of repeated and frequent
acoustic disturbance, some animals may habituate or learn to tolerate
the new baseline or fluctuations in noise level. While some animals may
not return to an area, or may begin using an area differently due to
training and testing activities, most animals are expected to return to
their usual locations and behavior.
Effects of Habitat Impacts on Marine Mammals
The proposed Civilian Port Defense training activities are not
expected to have any habitat-related effects that cause significant or
long-term consequences for individual marine mammals, their
populations, or prey species. Based on the discussions above, there
will be no loss or modification of marine mammal habitat and as a
result no impacts to marine mammal populations.
Proposed Mitigation
In order to issue an incidental take authorization under section
101(a)(5)(A) and (D) of the MMPA, NMFS must set forth the ``permissible
methods of taking pursuant to such activity, and other means of
effecting the least practicable adverse impact on such species or stock
and its habitat, paying particular attention to rookeries, mating
grounds, and areas of similar significance.'' NMFS' duty under this
``least practicable adverse impact'' standard is to prescribe
mitigation reasonably designed to minimize, to the extent practicable,
any adverse population-level impacts, as well as habitat impacts. While
population-level impacts can be minimized by reducing impacts on
individual marine mammals, not all takes translate to population-level
impacts. NMFS' primary objective under the ``least practicable adverse
impact'' standard is to design mitigation targeting those impacts on
individual marine mammals that are most likely to lead to adverse
population-level effects.
The NDAA of 2004 amended the MMPA as it relates to military-
readiness activities and the ITA process such that ``least practicable
adverse impact'' shall include consideration of personnel safety,
practicality of implementation, and impact on the effectiveness of the
``military readiness activity.'' The training activities described in
the Navy's application are considered military readiness activities.
NMFS reviewed the proposed activities and the proposed mitigation
measures as described in the application to determine if they would
result in the least practicable adverse effect on marine mammals, which
includes a careful balancing of the likely benefit of any particular
measure to the marine mammals with the likely effect of that measure on
personnel safety, practicality of implementation, and impact on the
effectiveness of the ``military-readiness activity.'' Included below
are the mitigation measures the Navy proposed in their application.
NMFS worked with the Navy to develop these proposed measures, and they
are informed by years of experience and monitoring.
The Navy's proposed mitigation measures are modifications to the
proposed activities that are implemented for the sole purpose of
reducing a specific potential environmental impact on a particular
resource. These do not include standard operating procedures, which are
established for reasons other than environmental benefit. Most of the
following proposed mitigation measures are currently, or were
previously, implemented as a result of past environmental compliance
documents. The Navy's overall approach to assessing potential
mitigation measures is based on two principles: (1) Mitigation measures
will be effective at reducing potential impacts on the resource, and
(2) from a military perspective, the mitigation measures are
practicable, executable, and safety and readiness will not be impacted.
The mitigation measures applicable to the proposed Civilian Port
Defense training activities are the same as those identified in the
Mariana Islands Training and Testing Environmental Impact Statement/
Overseas Environmental Impact Statement (MITT EIS/OEIS), Chapter 5. All
mitigation measures which could be applicable to the proposed
activities are provided below. For the mitigation measures described
below, the Lookout Procedures and Mitigation Zone Procedure sections
from the MITT EIS/OEIS have been combined. For details regarding the
methodology for analyzing each measure, see the MITT EIS/OEIS, Chapter
5.
Lookout Procedure Measures
The Navy will have two types of lookouts for the purposes of
conducting visual observations: (1) Those positioned on surface ships,
and (2) those positioned in aircraft or on boats. Lookouts positioned
on surface ships will be dedicated solely to diligent observation of
the air and surface of the water. They will have multiple observation
objectives, which include but are not limited to detecting the presence
of biological resources and recreational or fishing boats, observing
mitigation zones, and monitoring for vessel and personnel safety
concerns. Lookouts positioned on surface ships will typically be
personnel already standing watch or existing members of the bridge
watch team who become temporarily relieved of job responsibilities that
would divert their attention from observing the air or surface of the
water (such as navigation of a vessel).
Due to aircraft and boat manning and space restrictions, Lookouts
positioned in aircraft or on boats will consist of the aircraft crew,
pilot, or boat crew. Lookouts positioned in aircraft and boats may
necessarily be responsible for tasks in addition to observing the air
or surface of the water (for example,
[[Page 53675]]
navigation of a helicopter or rigid hull inflatable boat). However,
aircraft and boat lookouts will, to the maximum extent practicable and
consistent with aircraft and boat safety and training requirements,
comply with the observation objectives described above for Lookouts
positioned on surface ships.
Mitigation Measures
High-Frequency Active Sonar
The Navy will have one Lookout on ships or aircraft conducting
high-frequency active sonar activities associated with mine warfare
activities at sea.
Mitigation will include visual observation from a vessel or
aircraft (with the exception of platforms operating at high altitudes)
immediately before and during active transmission within a mitigation
zone of 200 yards (yds. [183 m]) from the active sonar source. If the
source can be turned off during the activity, active transmission will
cease if a marine mammal is sighted within the mitigation zone. Active
transmission will recommence if any one of the following conditions is
met: (1) The animal is observed exiting the mitigation zone, (2) the
animal is thought to have exited the mitigation zone based on a
determination of its course and speed and the relative motion between
the animal and the source, (3) the mitigation zone has been clear from
any additional sightings for a period of 10 minutes for an aircraft-
deployed source, (4) the mitigation zone has been clear from any
additional sightings for a period of 30 minutes for a vessel-deployed
source, (5) the vessel or aircraft has repositioned itself more than
400 yds (366 m) away from the location of the last sighting, or (6) the
vessel concludes that dolphins are deliberately closing in to ride the
vessel's bow wave (and there are no other marine mammal sightings
within the mitigation zone).
Physical Disturbance and Strike
Although the Navy does not anticipate that any marine mammals would
be struck during the conduct of Civilian Port Defense training
activities, the mitigation measures below will be implemented and
adhered to.
Vessels--While underway, vessels will have a minimum of one
Lookout. Vessels will avoid approaching marine mammals head on and will
maneuver to maintain a mitigation zone of 500 yds (457 m) around
observed whales, and 200 yds (183 m) around all other marine mammals
(except bow riding dolphins), providing it is safe to do so.
Towed In-Water Devices--The Navy will have one Lookout during
activities using towed in-water devices when towed from a manned
platform.
The Navy will ensure that towed in-water devices being towed from
manned platforms avoid coming within a mitigation zone of 250 yds (229
m) around any observed marine mammal, providing it is safe to do so.
Mitigation Conclusions
NMFS has carefully evaluated the Navy's proposed mitigation
measures--many of which were developed with NMFS' input during previous
Navy Training and Testing authorizations--and considered a range of
other measures in the context of ensuring that NMFS prescribes the
means of effecting the least practicable adverse impact on the affected
marine mammal species and stocks and their habitat. Our evaluation of
potential measures included consideration of the following factors in
relation to one another: The manner in which, and the degree to which,
the successful implementation of the mitigation measures is expected to
reduce the likelihood and/or magnitude of adverse impacts to marine
mammal species and stocks and their habitat; the proven or likely
efficacy of the measures; and the practicability of the suite of
measures for applicant implementation, including consideration of
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
Any mitigation measure(s) prescribed by NMFS should be able to
accomplish, have a reasonable likelihood of accomplishing (based on
current science), or contribute to accomplishing one or more of the
general goals listed below:
a. Avoid or minimize injury or death of marine mammals wherever
possible (goals b, c, and d may contribute to this goal).
b. Reduce the number of marine mammals (total number or number at
biologically important time or location) exposed to received levels of
MFAS/HFAS, underwater detonations, or other activities expected to
result in the take of marine mammals (this goal may contribute to a,
above, or to reducing harassment takes only).
c. Reduce the number of times (total number or number at
biologically important time or location) individuals would be exposed
to received levels of MFAS/HFAS, underwater detonations, or other
activities expected to result in the take of marine mammals (this goal
may contribute to a, above, or to reducing harassment takes only).
d. Reduce the intensity of exposures (either total number or number
at biologically important time or location) to received levels of MFAS/
HFAS, underwater detonations, or other activities expected to result in
the take of marine mammals (this goal may contribute to a, above, or to
reducing the severity of harassment takes only).
e. Avoid or minimize adverse effects to marine mammal habitat,
paying special attention to the food base, activities that block or
limit passage to or from biologically important areas, permanent
destruction of habitat, or temporary destruction/disturbance of habitat
during a biologically important time.
f. For monitoring directly related to mitigation--increase the
probability of detecting marine mammals, thus allowing for more
effective implementation of the mitigation (shut-down zone, etc.).
Based on our evaluation of the Navy's proposed measures, as well as
other measures considered by NMFS, NMFS has determined preliminarily
that the Navy's proposed mitigation measures are adequate means of
effecting the least practicable adverse impacts on marine mammals
species or stocks and their habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, while
also considering personnel safety, practicality of implementation, and
impact on the effectiveness of the military readiness activity.
The proposed IHA comment period provides the public an opportunity
to submit recommendations, views, and/or concerns regarding this action
and the proposed mitigation measures. While NMFS has determined
preliminarily that the Navy's proposed mitigation measures would effect
the least practicable adverse impact on the affected species or stocks
and their habitat, NMFS will consider all public comments to help
inform our final decision. Consequently, the proposed mitigation
measures may be refined, modified, removed, or added to prior to the
issuance of the authorization based on public comments received, and
where appropriate, further analysis of any additional mitigation
measures.
Proposed Monitoring and Reporting
Section 101(a)(5)(A) of the MMPA states that in order to issue an
ITA for an activity, NMFS must set forth ``requirements pertaining to
the monitoring and reporting of such taking.'' The MMPA implementing
regulations at 50 CFR 216.104 (a)(13) indicate that requests for LOAs
must include the suggested means of
[[Page 53676]]
accomplishing the necessary monitoring and reporting that will result
in increased knowledge of the species and of the level of taking or
impacts on populations of marine mammals that are expected to be
present.
Integrated Comprehensive Monitoring Program
The U.S. Navy has coordinated with NMFS to develop an overarching
program plan in which specific monitoring would occur. This plan is
called the Integrated Comprehensive Monitoring Program (ICMP) (U.S.
Department of the Navy, 2011). The ICMP has been developed in direct
response to Navy permitting requirements established in various MMPA
Final Rules, Endangered Species Act consultations, Biological Opinions,
and applicable regulations. As a framework document, the ICMP applies
by regulation to those activities on ranges and operating areas for
which the Navy is seeking or has sought incidental take authorizations.
The ICMP is intended to coordinate monitoring efforts across all
regions and to allocate the most appropriate level and type of effort
based on set of standardized research goals, and in acknowledgement of
regional scientific value and resource availability.
The ICMP is designed to be a flexible, scalable, and adjustable
plan. The ICMP is evaluated annually through the adaptive management
process to assess progress, provide a matrix of goals for the following
year, and make recommendations for refinement. Future monitoring will
address the following ICMP top-level goals through a series of regional
and ocean basin study questions with a priority study and funding focus
on species of interest as identified for each range complex.
An increase in our understanding of the likely occurrence
of marine mammals and/or ESA-listed marine species in the vicinity of
the action (i.e., presence, abundance, distribution, and/or density of
species);
An increase in our understanding of the nature, scope, or
context of the likely exposure of marine mammals and/or ESA-listed
species to any of the potential stressor(s) associated with the action
(e.g., tonal and impulsive sound), through better understanding of one
or more of the following: (1) The action and the environment in which
it occurs (e.g., sound source characterization, propagation, and
ambient noise levels); (2) the affected species (e.g., life history or
dive patterns); (3) the likely co-occurrence of marine mammals and/or
ESA-listed marine species with the action (in whole or part) associated
with specific adverse effects, and/or; (4) the likely biological or
behavioral context of exposure to the stressor for the marine mammal
and/or ESA-listed marine species (e.g., age class of exposed animals or
known pupping, calving or feeding areas);
An increase in our understanding of how individual marine
mammals or ESA-listed marine species respond (behaviorally or
physiologically) to the specific stressors associated with the action
(in specific contexts, where possible, e.g., at what distance or
received level);
An increase in our understanding of how anticipated
individual responses, to individual stressors or anticipated
combinations of stressors, may impact either: (1) The long-term fitness
and survival of an individual; or (2) the population, species, or stock
(e.g., through effects on annual rates of recruitment or survival);
An increase in our understanding of the effectiveness of
mitigation and monitoring measures;
A better understanding and record of the manner in which
the authorized entity complies with the ITA and Incidental Take
Statement;
An increase in the probability of detecting marine mammals
(through improved technology or methods), both specifically within the
safety zone (thus allowing for more effective implementation of the
mitigation) and in general, to better achieve the above goals; and
A reduction in the adverse impact of activities to the
least practicable level, as defined in the MMPA.
The ICMP will also address relative investments to different range
complexes based on goals across all range complexes, and monitoring
will leverage multiple techniques for data acquisition and analysis
whenever possible. Because the ICMP does not specify actual monitoring
field work or projects in a given area, it allows the Navy to
coordinate its monitoring to gather the best scientific data possible
across all areas in which the Navy operates. Details of the ICMP are
available online (http://www.navymarinespeciesmonitoring.us/).
Strategic Planning Process for Marine Species Monitoring
The Navy also developed the Strategic Planning Process for Marine
Species Monitoring, which establishes the guidelines and processes
necessary to develop, evaluate, and fund individual projects based on
objective scientific study questions. The process uses an underlying
framework designed around top-level goals, a conceptual framework
incorporating a progression of knowledge, and in consultation with a
Scientific Advisory Group and other regional experts. The Strategic
Planning Process for Marine Species Monitoring would be used to set
intermediate scientific objectives, identify potential species of
interest at a regional scale, and evaluate and select specific
monitoring projects to fund or continue supporting for a given fiscal
year. This process would also address relative investments to different
range complexes based on goals across all range complexes, and
monitoring would leverage multiple techniques for data acquisition and
analysis whenever possible. The Strategic Planning Process for Marine
Species Monitoring is also available online (http://www.navymarinespeciesmonitoring.us/).
Reporting
In order to issue an incidental take authorization for an activity,
section 101(a)(5)(A) and (D) of the MMPA states that NMFS must set
forth ``requirements pertaining to the monitoring and reporting of such
taking.'' Effective reporting is critical both to compliance as well as
ensuring that the most value is obtained from the required monitoring.
Some of the reporting requirements are still in development and the
final authorization may contain additional details not contained here.
Additionally, proposed reporting requirements may be modified, removed,
or added based on information or comments received during the public
comment period. Reports from individual monitoring events, results of
analyses, publications, and periodic progress reports for specific
monitoring projects would be posted to the Navy's Marine Species
Monitoring Web portal: http://www.navymarinespeciesmonitoring.us.
General Notification of Injured or Dead Marine Mammals--If any
injury or death of a marine mammal is observed during the Civilian Port
Defense training activities, the Navy will immediately halt the
activity and report the incident to NMFS following the standard
monitoring and reporting measures consistent with the MITT EIS/OEIS.
The reporting measures include the following procedures:
Navy personnel shall ensure that NMFS (regional stranding
coordinator) is notified immediately (or as soon as clearance
procedures allow) if an injured or dead marine mammal is found during
or shortly after, and in the vicinity of, any Navy training activity
utilizing high-frequency active sonar. The Navy shall provide NMFS with
species or description of the animal(s),
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the condition of the animal(s) (including carcass condition if the
animal is dead), location, time of first discovery, observed behaviors
(if alive), and photo or video (if available). The Navy shall consult
the Stranding Response and Communication Plan to obtain more specific
reporting requirements for specific circumstances.
Vessel Strike--Vessel strike during Navy Civilian Port Defense
activities in the Study Area is not anticipated; however, in the event
that a Navy vessel strikes a whale, the Navy shall do the following:
Immediately report to NMFS (pursuant to the established
Communication Protocol) the:
Species identification (if known);
Location (latitude/longitude) of the animal (or location
of the strike if the animal has disappeared);
Whether the animal is alive or dead (or unknown); and
The time of the strike.
As soon as feasible, the Navy shall report to or provide to NMFS,
the:
Size, length, and description (critical if species is not
known) of animal;
An estimate of the injury status (e.g., dead, injured but
alive, injured and moving, blood or tissue observed in the water,
status unknown, disappeared, etc.);
Description of the behavior of the whale during event,
immediately after the strike, and following the strike (until the
report is made or the animal is no longer sighted);
Vessel class/type and operational status;
Vessel length;
Vessel speed and heading; and
To the best extent possible, obtain a photo or video of
the struck animal, if the animal is still in view.
Within 2 weeks of the strike, provide NMFS:
A detailed description of the specific actions of the
vessel in the 30-minute timeframe immediately preceding the strike,
during the event, and immediately after the strike (e.g., the speed and
changes in speed, the direction and changes in direction, other
maneuvers, sonar use, etc., if not classified);
A narrative description of marine mammal sightings during
the event and immediately after, and any information as to sightings
prior to the strike, if available; and use established Navy shipboard
procedures to make a camera available to attempt to capture photographs
following a ship strike.
NMFS and the Navy will coordinate to determine the services the
Navy may provide to assist NMFS with the investigation of the strike.
The response and support activities to be provided by the Navy are
dependent on resource availability, must be consistent with military
security, and must be logistically feasible without compromising Navy
personnel safety. Assistance requested and provided may vary based on
distance of strike from shore, the nature of the vessel that hit the
whale, available nearby Navy resources, operational and installation
commitments, or other factors.
Estimated Take by Incidental Harassment
In the Potential Effects section, NMFS' analysis identified the
lethal responses, physical trauma, sensory impairment (PTS, TTS, and
acoustic masking), physiological responses (particular stress
responses), and behavioral responses that could potentially result from
exposure to active sonar (MFAS/HFAS). In this section, the potential
effects to marine mammals from active sonar will be related to the MMPA
regulatory definitions of Level A and Level B harassment and attempt to
quantify the effects that might occur from the proposed activities in
the Study Area.
As mentioned previously, behavioral responses are context-
dependent, complex, and influenced to varying degrees by a number of
factors other than just received level. For example, an animal may
respond differently to a sound emanating from a ship that is moving
towards the animal than it would to an identical received level coming
from a vessel that is moving away, or to a ship traveling at a
different speed or at a different distance from the animal. At greater
distances, though, the nature of vessel movements could also
potentially not have any effect on the animal's response to the sound.
In any case, a full description of the suite of factors that elicited a
behavioral response would require a mention of the vicinity, speed and
movement of the vessel, or other factors. So, while sound sources and
the received levels are the primary focus of the analysis and those
that are laid out quantitatively in the regulatory text, it is with the
understanding that other factors related to the training are sometimes
contributing to the behavioral responses of marine mammals, although
they cannot be quantified.
Definition of Harassment
As mentioned previously, with respect to military readiness
activities, section 3(18)(B) of the MMPA defines ``harassment'' as:
``(i) any act that injures or has the significant potential to injure a
marine mammal or marine mammal stock in the wild [Level A Harassment];
or (ii) any act that disturbs or is likely to disturb a marine mammal
or marine mammal stock in the wild by causing disruption of natural
behavioral patterns, including, but not limited to, migration,
surfacing, nursing, breeding, feeding, or sheltering, to a point where
such behavioral patterns are abandoned or significantly altered [Level
B Harassment].'' It is important to note that, as Level B harassment is
interpreted here and quantified by the behavioral thresholds described
below, the fact that a single behavioral pattern (of unspecified
duration) is abandoned or significantly altered and classified as a
Level B take does not mean, necessarily, that the fitness of the
harassed individual is affected either at all or significantly, or
that, for example, a preferred habitat area is abandoned. Further
analysis of context and duration of likely exposures and effects is
necessary to determine the impacts of the estimated effects on
individuals and how those may translate to population level impacts,
and is included in the Analysis and Negligible Impact Determination.
Level B Harassment
Of the potential effects that were described earlier in this
document, the following are the types of effects that fall into the
Level B harassment category:
Behavioral Harassment--Behavioral disturbance that rises to the
level described in the definition above, when resulting from exposures
to non-impulsive or impulsive sound, is considered Level B harassment.
Some of the lower level physiological stress responses discussed
earlier would also likely co-occur with the predicted harassments,
although these responses are more difficult to detect and fewer data
exist relating these responses to specific received levels of sound.
When Level B harassment is predicted based on estimated behavioral
responses, those takes may have a stress-related physiological
component as well.
As the statutory definition is currently applied, a wide range of
behavioral reactions may qualify as Level B harassment under the MMPA,
including but not limited to avoidance of the sound source, temporary
changes in vocalizations or dive patters, temporary avoidance of an
area, or temporary disruption of feeding, migrating, or reproductive
behaviors. The estimates calculated by the Navy using the acoustic
thresholds do not differentiate between the different types of
potential behavioral reactions. Nor do the
[[Page 53678]]
estimates provide information regarding the potential fitness or other
biological consequences of the reactions on the affected individuals.
We therefore consider the available scientific evidence to determine
the likely nature of the modeled behavioral responses and the potential
fitness consequences for affected individuals.
Temporary Threshold Shift (TTS)--As discussed previously, TTS can
affect how an animal behaves in response to the environment, including
conspecifics, predators, and prey. The following physiological
mechanisms are thought to play a role in inducing auditory fatigue:
Effects to sensory hair cells in the inner ear that reduce their
sensitivity, modification of the chemical environment within the
sensory cells; residual muscular activity in the middle ear,
displacement of certain inner ear membranes; increased blood flow; and
post-stimulatory reduction in both efferent and sensory neural output.
Ward (1997) suggested that when these effects result in TTS rather than
PTS, they are within the normal bounds of physiological variability and
tolerance and do not represent a physical injury. Additionally,
Southall et al. (2007) indicate that although PTS is a tissue injury,
TTS is not because the reduced hearing sensitivity following exposure
to intense sound results primarily from fatigue, not loss, of cochlear
hair cells and supporting structures and is reversible. Accordingly,
NMFS classifies TTS (when resulting from exposure to sonar and other
active acoustic sources and explosives and other impulsive sources) as
Level B harassment, not Level A harassment (injury).
Level A Harassment
Of the potential effects that were described earlier, the types of
effects that can fall into the Level A harassment category (unless they
further rise to the level of serious injury or mortality) include
permanent threshold shift (PTS), tissue damage due to acoustically
mediated bubble growth, tissue damage due to behaviorally mediated
bubble growth, physical disruption of tissues resulting from explosive
shock wave, and vessel strike and other physical disturbance (strike
from towed in-water devices). Level A harassment and mortality are not
anticipated to result from any of the proposed Civilian Port Defense
activities; therefore, these effects will not be discussed further.
Although the Navy does not anticipate that any marine mammals would be
struck during proposed Civilian Port Defense activities, the mitigation
measures described above in Proposed Mitigation will be implemented and
adhered to.
Criteria and Thresholds for Predicting Acoustic Impacts
Criteria and thresholds used for determining the potential effects
from the Civilian Port Defense activities are consistent with those
used in the Navy's Phase II Training and Testing EISs (e.g., HSTT,
MITT). Table 3 below provides the criteria and thresholds used in this
analysis for estimating quantitative acoustic exposures of marine
mammals from the proposed training activities. Weighting criteria are
shown in the table below. Southall et al. (2007) proposed frequency-
weighting to account for the frequency bandwidth of hearing in marine
mammals. Frequency-weighting functions are used to adjust the received
sound level based on the sensitivity of the animal to the frequency of
the sound. Details regarding these criteria and thresholds can be found
in Finneran and Jenkins (2012).
Table 3--Injury (PTS) and Disturbance (TTS, Behavioral) Thresholds for Underwater Sounds
----------------------------------------------------------------------------------------------------------------
Physiological criteria
Group Species Behavioral criteria -----------------------------------
Onset TTS Onset PTS
----------------------------------------------------------------------------------------------------------------
Low-Frequency Cetaceans....... All mysticetes....... Mysticete Dose 178 dB Sound 198 dB SEL (Type
Function (Type I Exposure Level II weighted).
weighted). (SEL) \1\ (Type
II weighted).
Mid-Frequency Cetaceans....... Most delphinids, Odontocete Dose 178 dB SEL (Type 198 dB SEL (Type
beaked whales, Function (Type I II weighted). II weighted).
medium and large weighted).
toothed whales.
High-Frequency Cetaceans...... Porpoises, River Odontocete Dose 152 dB SEL (Type 172 dB SEL (Type
dolphins, Function (Type I II weighted). II weighted).
Cephalorynchus spp., weighted).
Kogia sp.
Harbor Porpoises.............. Harbor porpoises..... 120 dB SPL, 152 dB SEL (Type 172 dB SEL (Type
unweighted. II weighted). II weighted).
Beaked Whales................. All Ziphiidae........ 140 dB SPL, 178 dB SEL (Type 198 dB SEL (Type
unweighted. II weighted). II weighted).
Phocidae (in water)........... Harbor, Bearded, Odontocete Dose 183 dB SEL (Type 197 dB SEL (Type
Hooded, Common, Function (Type I I weighted). I weighted).
Spotted, Ringed, weighted).
Baikal, Caspian,
Harp, Ribbon, Gray
seals, Monk,
Elephant, Ross,
Crabeater, Leopard,
and Weddell seals.
Otariidae (in water).......... Guadalupe fur seal, Odontocete Dose 206 dB SEL (Type 220 dB SEL (Type
Northern fur seal, Function (Type I I weighted). I weighted).
California sea lion, weighted).
Steller sea lion.
----------------------------------------------------------------------------------------------------------------
As discussed earlier, factors other than received level (such as
distance from or bearing to the sound source, context of animal at time
of exposure) can affect the way that marine mammals respond; however,
data to support a quantitative analysis of those (and other factors) do
not currently exist. It is also worth specifically noting that while
context is very important in marine mammal response, given otherwise
equivalent context, the severity of a marine mammal behavioral response
is also expected to increase with received level (Houser and Moore,
2014). NMFS will continue to modify these criteria as new data become
available and can be appropriately and effectively incorporated.
Marine Mammal Density Estimates
A quantitative analysis of impacts on a species requires data on
the abundance and distribution of the species population in the
potentially impacted area. The most appropriate unit of metric for this
type of analysis is density, which is described as the number of
animals present per unit area.
[[Page 53679]]
There is no single source of density data for every area, species,
and season because of the fiscal costs, resources, and effort involved
in NMFS providing enough survey coverage to sufficiently estimate
density. Therefore, to characterize the marine species density for
large areas such as the Study Area, the Navy needed to compile data
from multiple sources. Each data source may use different methods to
estimate density, of which, uncertainty in the estimate can be directly
related to the method applied. To develop a database of marine species
density estimates, the Navy, in consultation with NMFS experts, adopted
a protocol to select the best available data sources (including
habitat-based density models, line-transect analyses, and peer-reviewed
published studies) based on species, area, and season (see the Navy's
Pacific Marine Species Density Database Technical Report; U.S.
Department of the Navy, 2012, 2014). The resulting Geographic
Information System (GIS) database includes one single spatial and
seasonal density value for every marine mammal present within the Study
Area.
The Navy Marine Species Density Database includes a compilation of
the best available density data from several primary sources and
published works including survey data from NMFS within the U.S. EEZ.
NMFS is the primary agency responsible for estimating marine mammal and
sea turtle density within the U.S. EEZ. NMFS publishes annual SARs for
various regions of U.S. waters and covers all stocks of marine mammals
within those waters. The majority of species that occur in the Study
Area are covered by the Pacific Region Stock Assessment Report
(Carretta et al., 2014). Other independent researchers often publish
density data or research covering a particular marine mammal species,
which is integrated into the NMFS SARs.
For most cetacean species, abundance is estimated using line-
transect methods that employ a standard equation to derive densities
based on sighting data collected from systematic ship or aerial
surveys. More recently, habitat-based density models have been used
effectively to model cetacean density as a function of environmental
variables (e.g., Redfern et al., 2006; Barlow et al., 2009; Becker et
al., 2010; Becker et al., 2012a; Becker et al., 2012b; Becker, 2012c;
Forney et al., 2012). Where the data supports habitat based density
modeling, the Navy's database uses those density predictions. Habitat-
based density models allow predictions of cetacean densities on a finer
spatial scale than traditional line-transect analyses because cetacean
densities are estimated as a continuous function of habitat variables
(e.g., sea surface temperature, water depth). Within most of the
world's oceans, however there have not been enough systematic surveys
to allow for line-transect density estimation or the development of
habitat models. To get an approximation of the cetacean species
distribution and abundance for unsurveyed areas, in some cases it is
appropriate to extrapolate data from areas with similar oceanic
conditions where extensive survey data exist. Habitat Suitability
Indexes or Relative Environmental Suitability have also been used in
data-limited areas to estimate occurrence based on existing
observations about a given species' presence and relationships between
basic environmental conditions (Kaschner et al., 2006).
Methods used to estimate pinniped at-sea density are generally
quite different than those described above for cetaceans. Pinniped
abundance is generally estimated via shore counts of animals at known
rookeries and haulout sites. For example, for species such as the
California sea lion, population estimates are based on counts of pups
at the breeding sites (Carretta et al., 2014). However, this method is
not appropriate for other species such as harbor seals, whose pups
enter the water shortly after birth. Population estimates for these
species are typically made by counting the number of seals ashore and
applying correction factors based on the proportion of animals
estimated to be in the water (Carretta et al., 2014). Population
estimates for pinniped species that occur in the Study Area are
provided in the Pacific Region Stock Assessment Report (Carretta et
al., 2014). Translating these population estimates to in-water
densities presents challenges because the percentage of seals or sea
lions at sea compared to those on shore is species-specific and depends
on gender, age class, time of year (molt and breeding/pupping seasons),
foraging range, and for species such as harbor seal, time of day and
tide level. These parameters were identified from the literature and
used to establish correction factors which were then applied to
estimate the proportion of pinnipeds that would be at sea within the
Study Area for a given season.
Density estimates for each species in the Study Area, and the
sources for these estimates, are provided in Chapter 4 of the
application and in the Navy's Pacific Marine Species Density Database
Technical Report.
Quantitative Modeling To Estimate Take
The Navy performed a quantitative analysis to estimate the number
of mammals that could be exposed to the acoustic transmissions during
the proposed Civilian Port Defense activities. Inputs to the
quantitative analysis included marine mammal density estimates, marine
mammal depth occurrence distributions (Watwood and Buonantony 2012),
oceanographic and environmental data, marine mammal hearing data, and
criteria and thresholds for levels of potential effects. The
quantitative analysis consists of computer modeled estimates and a
post-model analysis to determine the number of potential mortalities
and harassments. The model calculates sound energy propagation from the
proposed sonars, the sound received by animat (virtual animal)
dosimeters representing marine mammals distributed in the area around
the modeled activity, and whether the sound received by a marine mammal
exceeds the thresholds for effects. The model estimates are then
further analyzed to consider animal avoidance and implementation of
mitigation measures, resulting in final estimates of effects due to the
proposed training activities.
The Navy developed a set of software tools and compiled data for
estimating acoustic effects on marine mammals without consideration of
behavioral avoidance or Navy's standard mitigations. These databases
and tools collectively form the Navy Acoustic Effects Model (NAEMO). In
NAEMO, animats (virtual animals) are distributed non-uniformly based on
species-specific density, depth distribution, and group size
information. Animats record energy received at their location in the
water column. A fully three-dimensional environment is used for
calculating sound propagation and animat exposure in NAEMO. Site-
specific bathymetry, sound speed profiles, wind speed, and bottom
properties are incorporated into the propagation modeling process.
NAEMO calculates the likely propagation for various levels of energy
(sound or pressure) resulting from each source used during the training
event.
NAEMO then records the energy received by each animat within the
energy footprint of the event and calculates the number of animats
having received levels of energy exposures that fall within defined
impact thresholds. Predicted effects on the animats within a scenario
are then tallied and the highest order effect (based on severity of
criteria; e.g., PTS over TTS) predicted for a given animat is assumed.
Each
[[Page 53680]]
scenario or each 24-hour period for scenarios lasting greater than 24
hours is independent of all others, and therefore, the same individual
marine animal could be impacted during each independent scenario or 24-
hour period. In few instances, although the activities themselves all
occur within the Study Area, sound may propagate beyond the boundary of
the Study Area. Any exposures occurring outside the boundary of the
Study Area are counted as if they occurred within the Study Area
boundary. NAEMO provides the initial estimated impacts on marine
species with a static horizontal distribution. These model-estimated
results are then further analyzed to account for pre-activity avoidance
by sensitive species, mitigation (considering sound source and
platform), and avoidance of repeated sound exposures by marine mammals,
producing the final predictions of effects used in this request for an
IHA.
There are limitations to the data used in the acoustic effects
model, and the results must be interpreted within these context. While
the most accurate data and input assumptions have been used in the
modeling, when there is a lack of definitive data to support an aspect
of the modeling, modeling assumptions believed to overestimate the
number of exposures have been chosen:
Animats are modeled as being underwater, stationary, and
facing the source and therefore always predicted to receive the maximum
sound level (i.e., no porpoising or pinnipeds' heads above water). Some
odontocetes have been shown to have directional hearing, with best
hearing sensitivity facing a sound source and higher hearing thresholds
for sounds propagating towards the rear or side of an animal (Kastelein
et al. 2005; Mooney et al. 2008; Popov and Supin 2009).
Animats do not move horizontally (but change their
position vertically within the water column), which may overestimate
physiological effects such as hearing loss, especially for slow moving
or stationary sound sources in the model.
Animats are stationary horizontally and therefore do not
avoid the sound source, unlike in the wild where animals would most
often avoid exposures at higher sound levels, especially those
exposures that may result in PTS.
Multiple exposures within any 24-hour period are
considered one continuous exposure for the purposes of calculating the
temporary or permanent hearing loss, because there are not sufficient
data to estimate a hearing recovery function for the time between
exposures.
Mitigation measures that are implemented were not
considered in the model. In reality, sound-producing activities would
be reduced, stopped, or delayed if marine mammals are detected within
the mitigation zones around sound sources.
Because of these inherent model limitations and simplifications,
model-estimated results must be further analyzed, considering such
factors as the range to specific effects, avoidance, and the likelihood
of successfully implementing mitigation measures, in order to determine
the final estimate of potential takes.
Impacts on Marine Mammals
Range to Effects--Table 4 provides range to effects for active
acoustic sources to specific criteria determined using NAEMO. Marine
mammals within these ranges would be predicted to receive the
associated effect. Range to effects is important information in not
only predicting acoustic impacts, but also in verifying the accuracy of
model results against real-world situations and determining adequate
mitigation ranges to avoid higher level effects, especially
physiological effects to marine mammals. Therefore, the ranges in Table
4 provide realistic maximum distances over which the specific effects
from the use of the AN/SQQ-32 high frequency sonar, the only acoustic
source to be used in the proposed activities that requires quantitative
analysis, would be possible.
Table 4--Maximum Range to Temporary Threshold Shift and Behavioral Effects From the AN/SQQ-32 in the Los Angeles/
Long Beach Study Area
----------------------------------------------------------------------------------------------------------------
Range to effects cold season Range to effects warm season
(m) (m)
Hearing group ---------------------------------------------------------------
Behavioral TTS Behavioral TTS
----------------------------------------------------------------------------------------------------------------
Low Frequency Cetacean.......................... 2,800 <50 1,900 <50
Mid-Frequency Cetacean.......................... 3,550 <50 2,550 <50
High Frequency Cetacean......................... 3,550 95 2,550 195
Phocidae water.................................. 3,450 <50 2,500 <50
Otariidae Odobenidae water...................... 3,350 <50 2,200 <50
----------------------------------------------------------------------------------------------------------------
Avoidance Behavior and Mitigation Measures--When sonar is active,
exposure to increased sound pressure levels would likely involve
individuals that are moving through the area during foraging trips.
Pinnipeds may also be exposed enroute to haul-out sites. As discussed
further in Chapter 7 of the application and in Analysis and Negligible
Impact Determination below, if exposure were to occur, both pinnipeds
and cetaceans could exhibit behavioral changes such as increased
swimming speeds, increased surfacing time, or decreased foraging. Most
likely, individuals affected by elevated underwater noise would move
away from the sound source and be temporarily displaced from the
proposed Study Area. Any effects experienced by individual marine
mammals are anticipated to be limited to short-term disturbance of
normal behavior, temporary displacement or disruption of animals which
may occur near the proposed training activities. Therefore, the
exposures requested are expected to have no more than a minor effect on
individual animals and no adverse effect on the populations of these
species.
Results from the quantitative analysis should be regarded as
conservative estimates that are strongly influenced by limited marine
mammal population data. While the numbers generated from the
quantitative analysis provide conservative overestimates of marine
mammal exposures, the short duration, limited geographic extent of
Civilian Port Defense training activities, and mitigation measures
would further limit actual exposures.
Incidental Take Request
The Navy's Draft EA for 2015 West Coast Civilian Port Defense
training activities analyzed the following stressors for potential
impacts to marine mammals:
[[Page 53681]]
Acoustic (sonar sources, vessel noise, aircraft noise)
Energy (electromagnetic devices and lasers)
Physical disturbance and strikes (vessels, in-water devices,
seafloor objects)
NMFS and the Navy determined the only stressor that could
potentially result in the incidental taking of marine mammals per the
definition of MMPA harassment from the Civilian Port Defense activities
within the Study Area is from acoustic transmissions related to high-
frequency sonar.
The methods of incidental take associated with the acoustic
transmissions from the proposed Civilian Port Defense are described
within Chapter 2 of the application. Acoustic transmissions have the
potential to temporarily disturb or displace marine mammals.
Specifically, only underwater active transmissions may result in the
``take'' in the form of Level B harassment.
Level A harassment and mortality are not anticipated to result from
any of the proposed Civilian Port Defense activities. Furthermore, Navy
mitigation and monitoring measures will be implemented to further
minimize the potential for Level B takes of marine mammals.
A detailed analysis of effects due to marine mammal exposures to
non-impulsive sources (i.e., active sonar) in the Study Area is
presented in Chapter 6 of the application and in the Estimated Take by
Incidental Harassment section of this proposed IHA. Based on the
quantitative acoustic modeling and analysis described in Chapter 6 of
the application, Table 5 summarizes the Navy's final take request the
Civilian Port Defense training activities from October through November
2015.
Table 5--Total Number of Exposures Modeled and Requested per Species for
Civilian Port Defense Training Activities
------------------------------------------------------------------------
Percentage of
Common name Level B takes stock taken
requested (%)
------------------------------------------------------------------------
Long-beaked common dolphin.............. 8 0.007
Short-beaked common dolphin............. 727 0.177
Risso's dolphin......................... 21 0.330
Pacific white-sided dolphin............. 40 0.149
Bottlenose dolphin coastal.............. 48 14.985
Harbor seal............................. 8 0.026
California sea lion..................... 46 0.015
-------------------------------
Total............................... 898 ..............
------------------------------------------------------------------------
Analysis and Negligible Impact Determination
Negligible impact is ``an impact resulting from the specified
activity that cannot be reasonably expected to, and is not reasonably
likely to, adversely affect the species or stock through effects on
annual rates of recruitment or survival'' (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes, alone, is not
enough information on which to base an impact determination, as the
severity of harassment may vary greatly depending on the context and
duration of the behavioral response, many of which would not be
expected to have deleterious impacts on the fitness of any individuals.
In determining whether the expected takes will have a negligible
impact, in addition to considering estimates of the number of marine
mammals that might be ``taken'', NMFS must consider other factors, such
as the likely nature of any responses (their intensity, duration,
etc.), the context of any responses (critical reproductive time or
location, migration, etc.), as well as the number and nature (e.g.,
severity) of estimated Level A harassment takes, the number of
estimated mortalities, and the status of the species.
To avoid repetition, we provide some general analysis immediately
below that applies to all the species listed in Table 5, given that
some of the anticipated effects (or lack thereof) of the Navy's
training activities on marine mammals are expected to be relatively
similar in nature. However, below that, we break our analysis into
species to provide more specific information related to the anticipated
effects on individuals or where there is information about the status
or structure of any species that would lead to a differing assessment
of the effects on the population.
Behavioral Harassment
As discussed previously in this document, marine mammals can
respond to MFAS/HFAS in many different ways, a subset of which
qualifies as harassment (see Behavioral Harassment). One thing that the
Level B harassment take estimates do not take into account is the fact
that most marine mammals will likely avoid strong sound sources to one
extent or another. Although an animal that avoids the sound source will
likely still be taken in some instances (such as if the avoidance
results in a missed opportunity to feed, interruption of reproductive
behaviors, etc.), in other cases avoidance may result in fewer
instances of take than were estimated or in the takes resulting from
exposure to a lower received level than was estimated, which could
result in a less severe response. An animal's exposure to a higher
received level is more likely to result in a behavioral response that
is more likely to adversely affect the health of the animal.
Specifically, given a range of behavioral responses that may be
classified as Level B harassment, to the degree that higher received
levels are expected to result in more severe behavioral responses, only
a small percentage of the anticipated Level B harassment from Navy
activities might necessarily be expected to potentially result in more
severe responses, especially when the distance from the source at which
the levels below are received is considered. Marine mammals are able to
discern the distance of a given sound source, and given other equal
factors (including received level), they have been reported to respond
more to sounds that are closer (DeRuiter et al., 2013). Further, the
estimated number of responses do not reflect either the duration or
context of those anticipated responses, some of which will be of very
short duration, and other factors should be considered
[[Page 53682]]
when predicting how the estimated takes may affect individual fitness.
Although the Navy has been monitoring the effects of MFAS/HFAS on
marine mammals since 2006, and research on the effects of active sonar
is advancing, our understanding of exactly how marine mammals in the
Study Area will respond to MFAS/HFAS is still growing. The Navy has
submitted reports from more than 60 major exercises across Navy range
complexes that indicate no behavioral disturbance was observed. One
cannot conclude from these results that marine mammals were not
harassed from MFAS/HFAS, as a portion of animals within the area of
concern were not seen, the full series of behaviors that would more
accurately show an important change is not typically seen (i.e., only
the surface behaviors are observed), and some of the non-biologist
watchstanders might not be well-qualified to characterize behaviors.
However, one can say that the animals that were observed did not
respond in any of the obviously more severe ways, such as panic,
aggression, or anti-predator response.
Diel Cycle
As noted previously, many animals perform vital functions, such as
feeding, resting, traveling, and socializing on a diel cycle (24-hour
cycle). Behavioral reactions to noise exposure (when taking place in a
biologically important context, such as disruption of critical life
functions, displacement, or avoidance of important habitat) are more
likely to be significant if they last more than one diel cycle or recur
on subsequent days (Southall et al., 2007). Consequently, a behavioral
response lasting less than one day and not recurring on subsequent days
is not considered severe unless it could directly affect reproduction
or survival (Southall et al., 2007). Note that there is a difference
between multiple-day substantive behavioral reactions and multiple-day
anthropogenic activities. For example, just because at-sea exercises
last for multiple days does not necessarily mean that individual
animals are either exposed to those exercises for multiple days or,
further, exposed in a manner resulting in a sustained multiple day
substantive behavioral response. Additionally, the Navy does not
necessarily operate active sonar the entire time during an exercise.
While it is certainly possible that these sorts of exercises could
overlap with individual marine mammals multiple days in a row at levels
above those anticipated to result in a take, because of the factors
mentioned above, it is considered not to be likely for the majority of
takes, does not mean that a behavioral response is necessarily
sustained for multiple days, and still necessitates the consideration
of likely duration and context to assess any effects on the
individual's fitness.
TTS
As mentioned previously, TTS can last from a few minutes to days,
be of varying degree, and occur across various frequency bandwidths,
all of which determine the severity of the impacts on the affected
individual, which can range from minor to more severe. The TTS
sustained by an animal is primarily classified by three
characteristics:
1. Frequency--Available data (of mid-frequency hearing specialists
exposed to mid- or high-frequency sounds; Southall et al., 2007)
suggest that most TTS occurs in the frequency range of the source up to
one octave higher than the source (with the maximum TTS at \1/2\ octave
above). The more powerful MF sources used have center frequencies
between 3.5 and 8 kHz and the other unidentified MF sources are, by
definition, less than 10 kHz, which suggests that TTS induced by any of
these MF sources would be in a frequency band somewhere between
approximately 2 and 20 kHz. There are fewer hours of HF source use and
the sounds would attenuate more quickly, plus they have lower source
levels, but if an animal were to incur TTS from these sources, it would
cover a higher frequency range (sources are between 20 and 100 kHz,
which means that TTS could range up to 200 kHz; however, HF systems are
typically used less frequently and for shorter time periods than
surface ship and aircraft MF systems, so TTS from these sources is even
less likely).
2. Degree of the shift (i.e., by how many dB the sensitivity of the
hearing is reduced)--Generally, both the degree of TTS and the duration
of TTS will be greater if the marine mammal is exposed to a higher
level of energy (which would occur when the peak dB level is higher or
the duration is longer). The threshold for the onset of TTS was
discussed previously in this document. An animal would have to approach
closer to the source or remain in the vicinity of the sound source
appreciably longer to increase the received SEL, which would be
difficult considering the Lookouts and the nominal speed of an active
sonar vessel (10-15 knots). In the TTS studies, some using exposures of
almost an hour in duration or up to 217 SEL, most of the TTS induced
was 15 dB or less, though Finneran et al. (2007) induced 43 dB of TTS
with a 64-second exposure to a 20 kHz source. However, MFAS emits a
nominal ping every 50 seconds, and incurring those levels of TTS is
highly unlikely.
3. Duration of TTS (recovery time)--In the TTS laboratory studies,
some using exposures of almost an hour in duration or up to 217 SEL,
almost all individuals recovered within 1 day (or less, often in
minutes), although in one study (Finneran et al., 2007), recovery took
4 days.
Based on the range of degree and duration of TTS reportedly induced
by exposures to non-pulse sounds of energy higher than that to which
free-swimming marine mammals in the field are likely to be exposed
during MFAS/HFAS training exercises in the Study Area, it is unlikely
that marine mammals would ever sustain a TTS from active sonar that
alters their sensitivity by more than 20 dB for more than a few days
(and any incident of TTS would likely be far less severe due to the
short duration of the majority of the exercises and the speed of a
typical vessel). Also, for the same reasons discussed in the Diel Cycle
section, and because of the short distance within which animals would
need to approach the sound source, it is unlikely that animals would be
exposed to the levels necessary to induce TTS in subsequent time
periods such that their recovery is impeded. Additionally, though the
frequency range of TTS that marine mammals might sustain would overlap
with some of the frequency ranges of their vocalization types, the
frequency range of TTS from MFAS/HFAS (the source from which TTS would
most likely be sustained because the higher source level and slower
attenuation make it more likely that an animal would be exposed to a
higher received level) would not usually span the entire frequency
range of one vocalization type, much less span all types of
vocalizations or other critical auditory cues. If impaired, marine
mammals would typically be aware of their impairment and are sometimes
able to implement behaviors to compensate (see Acoustic Masking or
Communication Impairment section), though these compensations may incur
energetic costs.
Acoustic Masking or Communication Impairment
Masking only occurs during the time of the signal (and potential
secondary arrivals of indirect rays), versus TTS, which continues
beyond the duration of the signal. Standard MFAS/HFAS nominally pings
every 50 seconds for hull-mounted sources. For the sources for which we
know the pulse length, most are significantly shorter than hull-
[[Page 53683]]
mounted active sonar, on the order of several microseconds to tens of
microseconds. For hull-mounted active sonar, though some of the
vocalizations that marine mammals make are less than one second long,
there is only a 1 in 50 chance that they would occur exactly when the
ping was received, and when vocalizations are longer than one second,
only parts of them are masked. Alternately, when the pulses are only
several microseconds long, the majority of most animals' vocalizations
would not be masked. Masking effects from MFAS/HFAS are expected to be
minimal. If masking or communication impairment were to occur briefly,
it would be in the frequency range of MFAS/HFAS, which overlaps with
some marine mammal vocalizations; however, it would likely not mask the
entirety of any particular vocalization, communication series, or other
critical auditory cue, because the signal length, frequency, and duty
cycle of the MFAS/HFAS signal does not perfectly mimic the
characteristics of any marine mammal's vocalizations.
Important Marine Mammal Habitat
No critical habitat for marine mammals species protected under the
ESA has been designated in the Study Area. There are also no known
specific breeding or calving areas for marine mammals within the Study
Area.
Species-Specific Analysis
Long-beaked Common Dolphin--Long-beaked common dolphins that may be
found in the Study Area belong to the California stock (Carretta et
al., 2014). The Navy's acoustic analysis (quantitative modeling)
predicts that 8 instances of Level B harassment of long-beaked common
dolphin may occur from active sonar in the Study Area during Civilian
Port Defense training activities. These Level B takes are anticipated
to be in the form of behavioral reactions (3) and TTS (5) and no
injurious takes of long-beaked common dolphin are requested or proposed
for authorization. Relative to population size, these activities are
anticipated to result only in a limited number of level B harassment
takes. When the numbers of behavioral takes are compared to the
estimated stock abundance (stock abundance estimates are shown in Table
1) and if one assumes that each take happens to a separate animal, less
than 0.01 percent of the California stock of long-beaked common dolphin
would be behaviorally harassed during proposed training activities.
Behavioral reactions of marine mammals to sound are known to occur
but are difficult to predict. Recent behavioral studies indicate that
reactions to sounds, if any, are highly contextual and vary between
species and individuals within a species (Moretti et al., 2010;
Southall et al., 2011; Thompson et al., 2010; Tyack, 2009; Tyack et
al., 2011). Behavioral responses can range from alerting, to changing
their behavior or vocalizations, to avoiding the sound source by
swimming away or diving (Richardson, 1995; Nowacek, 2007; Southall et
al., 2007; Finneran and Jenkins, 2012). Long-beaked common dolphins
generally travel in large pods and should be visible from a distance in
order to implement mitigation measures and reduce potential impacts.
Many of the recorded long-beaked common dolphin vocalizations overlap
with the MFAS/HFAS TTS frequency range (2-20 kHz) (Moore and Ridgway,
1995; Ketten, 1998); however, NMFS does not anticipate TTS of a serious
degree or extended duration to occur as a result of exposure to MFAS/
HFAS. Recovery from a threshold shift (TTS) can take a few minutes to a
few days, depending on the exposure duration, sound exposure level, and
the magnitude of the initial shift, with larger threshold shifts and
longer exposure durations requiring longer recovery times (Finneran et
al., 2005; Mooney et al., 2009a; Mooney et al., 2009b; Finneran and
Schlundt, 2010). Large threshold shifts are not anticipated for these
activities because of the unlikelihood that animals will remain within
the ensonified area at high levels for the duration necessary to induce
larger threshold shifts. Threshold shifts do not necessarily affect all
hearing frequencies equally, so some threshold shifts may not interfere
with an animal's hearing of biologically relevant sounds.
Overall, the number of predicted behavioral reactions is low and
temporary behavioral reactions in long-beaked common dolphins are
unlikely to cause long-term consequences for individual animals or the
population. The Civilian Port Defense activities are not expected to
occur in an area/time of specific importance for reproductive, feeding,
or other known critical behaviors for long-beaked common dolphin. No
evidence suggests any major reproductive differences in comparison to
short-beaked common dolphins (Reeves et al., 2002). Short-beaked common
dolphin gestation is approximately 11 to 11.5 months in duration
(Danil, 2004; Murphy and Rogan, 2006) with most calves born from May to
September (Murphy and Rogan, 2006). Therefore, calving would not occur
during the Civilian Port Defense training timeframe. The California
stock of long-beaked common dolphin is not depleted under the MMPA.
Although there is no formal statistical trend analysis, over the last
30 years sighting and stranding data shows an increasing trend of long-
beaked common dolphins in California waters (Carretta et al., 2014).
Consequently, the activities are not expected to adversely impact
annual rates of recruitment or survival of long-beaked common dolphin.
Short-beaked Common Dolphin--Short-beaked common dolphins that may
be found in the Study Area belong to the California/Washington/Oregon
stock (Carretta et al., 2014). The Navy's acoustic analysis
(quantitative modeling) predicts that 727 instances of Level B
harassment of short-beaked common dolphin may occur from active sonar
in the Study Area during Civilian Port Defense training activities.
These Level B takes are anticipated to be in the form of behavioral
reactions (422) and TTS (305) and no injurious takes of short-beaked
common dolphin are requested or proposed for authorization. Relative to
population size, these activities are anticipated to result only in a
limited number of level B harassment takes. When the numbers of
behavioral takes are compared to the estimated stock abundance (stock
abundance estimates are shown in Table 1) and if one assumes that each
take happens to a separate animal, less than 0.18 percent of the
California/Washington/Oregon stock of short-beaked common dolphin would
be behaviorally harassed during proposed training activities.
Behavioral reactions of marine mammals to sound are known to occur
but are difficult to predict. Recent behavioral studies indicate that
reactions to sounds, if any, are highly contextual and vary between
species and individuals within a species (Moretti et al., 2010;
Southall et al., 2011; Thompson et al., 2010; Tyack, 2009; Tyack et
al., 2011). Behavioral responses can range from alerting, to changing
their behavior or vocalizations, to avoiding the sound source by
swimming away or diving (Richardson, 1995; Nowacek, 2007; Southall et
al., 2007; Finneran and Jenkins, 2012). Short-beaked common dolphins
generally travel in large pods and should be visible from a distance in
order to implement mitigation measures and reduce potential impacts.
Many of the recorded short-beaked common dolphin vocalizations overlap
with the MFAS/HFAS TTS frequency range (2-20 kHz) (Moore and Ridgway,
1995;
[[Page 53684]]
Ketten, 1998); however, NMFS does not anticipate TTS of a serious
degree or extended duration to occur as a result of exposure to MFAS/
HFAS. Recovery from a threshold shift (TTS) can take a few minutes to a
few days, depending on the exposure duration, sound exposure level, and
the magnitude of the initial shift, with larger threshold shifts and
longer exposure durations requiring longer recovery times (Finneran et
al., 2005; Mooney et al., 2009a; Mooney et al., 2009b; Finneran and
Schlundt, 2010). Large threshold shifts are not anticipated for these
activities because of the unlikelihood that animals will remain within
the ensonified area at high levels for the duration necessary to induce
larger threshold shifts. Threshold shifts do not necessarily affect all
hearing frequencies equally, so some threshold shifts may not interfere
with an animal's hearing of biologically relevant sounds.
Overall, the number of predicted behavioral reactions is low and
temporary behavioral reactions in short-beaked common dolphins are
unlikely to cause long-term consequences for individual animals or the
population. The Civilian Port Defense activities are not expected to
occur in an area/time of specific importance for reproductive, feeding,
or other known critical behaviors for long-beaked common dolphin.
Short-beaked common dolphin gestation is approximately 11 to 11.5
months in duration (Danil, 2004; Murphy and Rogan, 2006) with most
calves born from May to September (Murphy and Rogan, 2006). Therefore,
calving would not occur during the Civilian Port Defense training
timeframe. The California/Washington/Oregon stock of short-beaked
common dolphin is not depleted under the MMPA. Abundance off California
has increased dramatically since the late 1970s, along with a smaller
decrease in abundance in the eastern tropical Pacific, suggesting a
large-scale northward shift in the distribution of this species in the
eastern north Pacific (Forney and Barlow, 1998; Forney et al., 1995).
Consequently, the activities are not expected to adversely impact
annual rates of recruitment or survival of short-beaked common dolphin.
Risso's Dolphin--Risso's dolphins that may be found in the Study
Area belong to the California/Washington/Oregon stock (Carretta et al.,
2014). The Navy's acoustic analysis (quantitative modeling) predicts
that 21 instances of Level B harassment of Risso's dolphin may occur
from active sonar in the Study Area during Civilian Port Defense
training activities. These Level B takes are anticipated to be in the
form of behavioral reactions (16) and TTS (5) and no injurious takes of
Risso's dolphin are requested or proposed for authorization. Relative
to population size, these activities are anticipated to result only in
a limited number of level B harassment takes. When the numbers of
behavioral takes are compared to the estimated stock abundance (stock
abundance estimates are shown in Table 1) and if one assumes that each
take happens to a separate animal, approximately 0.33 percent of the
California/Washington/Oregon stock of Risso's dolphin would be
behaviorally harassed during proposed training activities.
Behavioral reactions of marine mammals to sound are known to occur
but are difficult to predict. Recent behavioral studies indicate that
reactions to sounds, if any, are highly contextual and vary between
species and individuals within a species (Moretti et al., 2010;
Southall et al., 2011; Thompson et al., 2010; Tyack, 2009; Tyack et
al., 2011). Behavioral responses can range from alerting, to changing
their behavior or vocalizations, to avoiding the sound source by
swimming away or diving (Richardson, 1995; Nowacek, 2007; Southall et
al., 2007; Finneran and Jenkins, 2012). Risso's dolphins generally
travel in large pods and should be visible from a distance in order to
implement mitigation measures and reduce potential impacts. Many of the
recorded Risso's dolphin vocalizations overlap with the MFAS/HFAS TTS
frequency range (2-20 kHz) (Corkeron and Van Parijs 2001); however,
NMFS does not anticipate TTS of a serious degree or extended duration
to occur as a result of exposure to MFAS/HFAS. Recovery from a
threshold shift (TTS) can take a few minutes to a few days, depending
on the exposure duration, sound exposure level, and the magnitude of
the initial shift, with larger threshold shifts and longer exposure
durations requiring longer recovery times (Finneran et al., 2005;
Mooney et al., 2009a; Mooney et al., 2009b; Finneran and Schlundt,
2010). Large threshold shifts are not anticipated for these activities
because of the unlikelihood that animals will remain within the
ensonified area at high levels for the duration necessary to induce
larger threshold shifts. Threshold shifts do not necessarily affect all
hearing frequencies equally, so some threshold shifts may not interfere
with an animal's hearing of biologically relevant sounds.
Overall, the number of predicted behavioral reactions is low and
temporary behavioral reactions in Risso's dolphins are unlikely to
cause long-term consequences for individual animals or the population.
The Civilian Port Defense activities are not expected to occur in an
area/time of specific importance for reproductive, feeding, or other
known critical behaviors for Risso's dolphin. The California/
Washington/Oregon stock of Risso's dolphin is not depleted under the
MMPA. The distribution of Risso's dolphins throughout the region is
highly variable, apparently in response to oceanographic changes
(Forney and Barlow, 1998). The status of Risso's dolphins off
California, Oregon and Washington relative to optimum sustainable
population is not known, and there are insufficient data to evaluate
potential trends in abundance. However, Civilian Port Defense training
activities are not expected to adversely impact annual rates of
recruitment or survival of Risso's dolphin for the reasons stated
above.
Pacific White-Sided Dolphin--Pacific white-sided dolphins that may
be found in the Study Area belong to the California/Washington/Oregon
stock (Carretta et al., 2014). The Navy's acoustic analysis
(quantitative modeling) predicts that 40 instances of Level B
harassment of Pacific white-sided dolphin may occur from active sonar
in the Study Area during Civilian Port Defense training activities.
These Level B takes are anticipated to be in the form of behavioral
reactions (21) and TTS (19) and no injurious takes of Pacific white-
sided dolphin are requested or proposed for authorization. Relative to
population size, these activities are anticipated to result only in a
limited number of level B harassment takes. When the numbers of
behavioral takes are compared to the estimated stock abundance (stock
abundance estimates are shown in Table 1) and if one assumes that each
take happens to a separate animal, less than 0.15 percent of the
California/Washington/Oregon stock of Pacific white-sided dolphin would
be behaviorally harassed during proposed training activities.
Behavioral reactions of marine mammals to sound are known to occur
but are difficult to predict. Recent behavioral studies indicate that
reactions to sounds, if any, are highly contextual and vary between
species and individuals within a species (Moretti et al., 2010;
Southall et al., 2011; Thompson et al., 2010; Tyack, 2009; Tyack et
al., 2011). Behavioral responses can range from alerting, to changing
their behavior or vocalizations, to avoiding the sound source by
swimming away or diving
[[Page 53685]]
(Richardson, 1995; Nowacek, 2007; Southall et al., 2007; Finneran and
Jenkins, 2012). Pacific white-sided dolphins generally travel in large
pods and should be visible from a distance in order to implement
mitigation measures and reduce potential impacts. Many of the recorded
Pacific white-sided dolphin vocalizations overlap with the MFAS/HFAS
TTS frequency range (2-20 kHz); however, NMFS does not anticipate TTS
of a serious degree or extended duration to occur as a result of
exposure to MFAS/HFAS. Recovery from a threshold shift (TTS) can take a
few minutes to a few days, depending on the exposure duration, sound
exposure level, and the magnitude of the initial shift, with larger
threshold shifts and longer exposure durations requiring longer
recovery times (Finneran et al., 2005; Mooney et al., 2009a; Mooney et
al., 2009b; Finneran and Schlundt, 2010). Large threshold shifts are
not anticipated for these activities because of the unlikelihood that
animals will remain within the ensonified area at high levels for the
duration necessary to induce larger threshold shifts. Threshold shifts
do not necessarily affect all hearing frequencies equally, so some
threshold shifts may not interfere with an animal's hearing of
biologically relevant sounds.
Overall, the number of predicted behavioral reactions is low and
temporary behavioral reactions in Pacific white-sided dolphins are
unlikely to cause long-term consequences for individual animals or the
population. The Civilian Port Defense activities are not expected to
occur in an area/time of specific importance for reproductive, feeding,
or other known critical behaviors for long-beaked common dolphin.
Pacific white-sided dolphin calves are typically born in the summer
months between April and early September (Black, 1994; NOAA, 2012;
Reidenberg and Laitman, 2002). This species is predominantly located
around the proposed Study Area in the colder winter months when neither
mating nor calving is expected, as both occur off the coast of Oregon
and Washington outside of the timeframe for the proposed activities
(October through November). The California/Washington/Oregon stock of
Pacific white-sided dolphin is not depleted under the MMPA. The stock
is considered stable, with no indications of any positive or negative
trends in abundance (NOAA, 2014). Consequently, the activities are not
expected to adversely impact annual rates of recruitment or survival of
Pacific white-sided dolphin.
Bottlenose Dolphin--Bottlenose dolphins that may be found in the
Study Area belong to the California Coastal stock (Carretta et al.,
2014). The Navy's acoustic analysis (quantitative modeling) predicts
that 48 instances of Level B harassment of bottlenose dolphin may occur
from active sonar in the Study Area during Civilian Port Defense
training activities. These Level B takes are anticipated to be in the
form of behavioral reactions (29) and TTS (19) and no injurious takes
of bottlenose dolphin are requested or proposed for authorization.
Relative to population size, these activities are anticipated to result
only in a limited number of level B harassment takes. When the numbers
of behavioral takes are compared to the estimated stock abundance
(stock abundance estimates are shown in Table 1) and if one assumes
that each take happens to a separate animal, less than 15 percent of
the Coastal stock of bottlenose dolphin would be behaviorally harassed
during proposed training activities.
Behavioral reactions of marine mammals to sound are known to occur
but are difficult to predict. Recent behavioral studies indicate that
reactions to sounds, if any, are highly contextual and vary between
species and individuals within a species (Moretti et al., 2010;
Southall et al., 2011; Thompson et al., 2010; Tyack, 2009; Tyack et
al., 2011). Behavioral responses can range from alerting, to changing
their behavior or vocalizations, to avoiding the sound source by
swimming away or diving (Richardson, 1995; Nowacek, 2007; Southall et
al., 2007; Finneran and Jenkins, 2012). Bottlenose dolphins generally
travel in large pods and should be visible from a distance in order to
implement mitigation measures and reduce potential impacts. Many of the
recorded bottlenose dolphin vocalizations overlap with the MFAS/HFAS
TTS frequency range (2-20 kHz); however, NMFS does not anticipate TTS
of a serious degree or extended duration to occur as a result of
exposure to MFAS/HFAS. Recovery from a threshold shift (TTS) can take a
few minutes to a few days, depending on the exposure duration, sound
exposure level, and the magnitude of the initial shift, with larger
threshold shifts and longer exposure durations requiring longer
recovery times (Finneran et al., 2005; Mooney et al., 2009a; Mooney et
al., 2009b; Finneran and Schlundt, 2010). Large threshold shifts are
not anticipated for these activities because of the unlikelihood that
animals will remain within the ensonified area at high levels for the
duration necessary to induce larger threshold shifts. Threshold shifts
do not necessarily affect all hearing frequencies equally, so some
threshold shifts may not interfere with an animal's hearing of
biologically relevant sounds.
Overall, the number of predicted behavioral reactions is low and
temporary behavioral reactions in bottlenose dolphins are unlikely to
cause long-term consequences for individual animals or the population.
The Civilian Port Defense activities are not expected to occur in an
area/time of specific importance for reproductive, feeding, or other
known critical behaviors for bottlenose dolphin. The California/
Washington/Oregon stock of bottlenose dolphin is not depleted under the
MMPA. In a comparison of abundance estimates from 1987-89 (n = 354),
1996-98 (n = 356), and 2004-05 (n = 323), Dudzik et al. (2006) found
that the population size has remained stable over this period of
approximately 20 years. Consequently, the activities are not expected
to adversely impact annual rates of recruitment or survival of
bottlenose dolphin.
Harbor Seal--Harbor seals that may be found in the Study Area
belong to the California stock (Carretta et al., 2014). Harbor seals
have not been observed on the mainland coast of Los Angeles, Orange,
and northern San Diego Counties (Henkel and Harvey, 2008; Lowry et al.,
2008). Thus, no harbor seal haul-outs are located within the proposed
Study Area. The Navy's acoustic analysis (quantitative modeling)
predicts that 8 instances of Level B harassment of harbor seal may
occur from active sonar in the Study Area during Civilian Port Defense
training activities. These Level B takes are anticipated to be in the
form of non-TTS behavioral reactions only and no injurious takes of
harbor seal are requested or proposed for authorization. Relative to
population size, these activities are anticipated to result only in a
limited number of level B harassment takes. When the numbers of
behavioral takes are compared to the estimated stock abundance (stock
abundance estimates are shown in Table 1) and if one assumes that each
take happens to a separate animal, less than 0.03 percent of the
California stock of harbor seal would be behaviorally harassed during
proposed training activities.
Research and observations show that pinnipeds in the water may be
tolerant of anthropogenic noise and activity (a review of behavioral
reactions by pinnipeds to impulsive and non-impulsive noise can be
found in
[[Page 53686]]
Richardson et al., 1995 and Southall et al., 2007). Available data,
though limited, suggest that exposures between approximately 90 and 140
dB SPL do not appear to induce strong behavioral responses in pinnipeds
exposed to nonpulse sounds in water (Jacobs and Terhune, 2002; Costa et
al., 2003; Kastelein et al., 2006c). Based on the limited data on
pinnipeds in the water exposed to multiple pulses (small explosives,
impact pile driving, and seismic sources), exposures in the
approximately 150 to 180 dB SPL range generally have limited potential
to induce avoidance behavior in pinnipeds (Harris et al., 2001;
Blackwell et al., 2004; Miller et al., 2004). If pinnipeds are exposed
to sonar or other active acoustic sources they may react in a number of
ways depending on their experience with the sound source and what
activity they are engaged in at the time of the acoustic exposure.
Pinnipeds may not react at all until the sound source is approaching
within a few hundred meters and then may alert, ignore the stimulus,
change their behaviors, or avoid the immediate area by swimming away or
diving. Effects on pinnipeds in the Study Area that are taken by Level
B harassment, on the basis of reports in the literature as well as Navy
monitoring from past activities, will likely be limited to reactions
such as increased swimming speeds, increased surfacing time, or
decreased foraging (if such activity were occurring). Most likely,
individuals will simply move away from the sound source and be
temporarily displaced from those areas, or not respond at all. In areas
of repeated and frequent acoustic disturbance, some animals may
habituate or learn to tolerate the new baseline or fluctuations in
noise level. Habituation can occur when an animal's response to a
stimulus wanes with repeated exposure, usually in the absence of
unpleasant associated events (Wartzok et al., 2003). While some animals
may not return to an area, or may begin using an area differently due
to training activities, most animals are expected to return to their
usual locations and behavior. Given their documented tolerance of
anthropogenic sound (Richardson et al., 1995 and Southall et al.,
2007), repeated exposures of harbor seals to levels of sound that may
cause Level B harassment are unlikely to result in hearing impairment
or to significantly disrupt foraging behavior.
Overall, the number of predicted behavioral reactions is low and
temporary behavioral reactions in harbor seals are unlikely to cause
long-term consequences for individual animals or the population. The
Civilian Port Defense activities are not expected to occur in an area/
time of specific importance for reproductive, feeding, or other known
critical behaviors for harbor seal. In California, harbor seals breed
from March to May and pupping occurs between April and May (Alden et
al., 2002; Reeves et al., 2002), neither of which occur within the
timeframe of the proposed activities. The California stock of harbor
seal is not depleted under the MMPA. Counts of harbor seals in
California increased from 1981 to 2004, although a review of harbor
seal dynamics through 1991 concluded that their status could not be
determined with certainty (Hanan, 1996). The population appears to be
stabilizing at what may be its carrying capacity. Consequently, the
activities are not expected to adversely impact annual rates of
recruitment or survival of harbor seal.
California Sea Lion--California sea lions that may be found in the
Study Area belong to the U.S. stock (Carretta et al., 2014). The Navy's
acoustic analysis (quantitative modeling) predicts that 46 instances of
Level B harassment of California sea lion may occur from active sonar
in the Study Area during Civilian Port Defense training activities.
These Level B takes are anticipated to be in the form of non-TTS
behavioral reactions only and no injurious takes of California sea
lions are requested or proposed for authorization. Relative to
population size, these activities are anticipated to result only in a
limited number of level B harassment takes. When the numbers of
behavioral takes are compared to the estimated stock abundance (stock
abundance estimates are shown in Table 1) and if one assumes that each
take happens to a separate animal, less than 0.02 percent of the U.S.
stock of California sea lions would be behaviorally harassed during
proposed training activities.
Research and observations show that pinnipeds in the water may be
tolerant of anthropogenic noise and activity (a review of behavioral
reactions by pinnipeds to impulsive and non-impulsive noise can be
found in Richardson et al., 1995 and Southall et al., 2007). Available
data, though limited, suggest that exposures between approximately 90
and 140 dB SPL do not appear to induce strong behavioral responses in
pinnipeds exposed to nonpulse sounds in water (Jacobs and Terhune,
2002; Costa et al., 2003; Kastelein et al., 2006c). Based on the
limited data on pinnipeds in the water exposed to multiple pulses
(small explosives, impact pile driving, and seismic sources), exposures
in the approximately 150 to 180 dB SPL range generally have limited
potential to induce avoidance behavior in pinnipeds (Harris et al.,
2001; Blackwell et al., 2004; Miller et al., 2004). If pinnipeds are
exposed to sonar or other active acoustic sources they may react in a
number of ways depending on their experience with the sound source and
what activity they are engaged in at the time of the acoustic exposure.
Pinnipeds may not react at all until the sound source is approaching
within a few hundred meters and then may alert, ignore the stimulus,
change their behaviors, or avoid the immediate area by swimming away or
diving. Effects on pinnipeds in the Study Area that are taken by Level
B harassment, on the basis of reports in the literature as well as Navy
monitoring from past activities will likely be limited to reactions
such as increased swimming speeds, increased surfacing time, or
decreased foraging (if such activity were occurring). Most likely,
individuals will simply move away from the sound source and be
temporarily displaced from those areas, or not respond at all. In areas
of repeated and frequent acoustic disturbance, some animals may
habituate or learn to tolerate the new baseline or fluctuations in
noise level. Habituation can occur when an animal's response to a
stimulus wanes with repeated exposure, usually in the absence of
unpleasant associated events (Wartzok et al., 2003). While some animals
may not return to an area, or may begin using an area differently due
to training activities, most animals are expected to return to their
usual locations and behavior. Given their documented tolerance of
anthropogenic sound (Richardson et al., 1995 and Southall et al.,
2007), repeated exposures of individuals to levels of sound that may
cause Level B harassment are unlikely to result in hearing impairment
or to significantly disrupt foraging behavior.
Overall, the number of predicted behavioral reactions is low and
temporary behavioral reactions in California sea lions are unlikely to
cause long-term consequences for individual animals or the population.
The Civilian Port Defense activities are not expected to occur in an
area/time of specific importance for reproductive, feeding, or other
known critical behaviors for California sea lions. It is likely that
male California sea lions will be primarily outside of the Study Area
during the timeframe of the proposed activities, but females may be
present. Typically
[[Page 53687]]
during the summer, California sea lions congregate near rookery islands
and specific open-water areas. The primary rookeries off the coast of
California are on San Nicolas, San Miguel, Santa Barbara, and San
Clemente Islands (Boeuf and Bonnell, 1980; Carretta et al., 2000; Lowry
et al., 1992; Lowry and Forney, 2005). In May or June, female sea lions
give birth, either on land or in water. Adult males establish breeding
territories, both on land and in water, from May to July. In addition
to the rookery sites, Santa Catalina Island is a major haul-out site
within the Southern California Bight (Boeuf, 2002). Thus, breeding and
pupping take place outside of the timeframe and location of the
proposed training activities. The U.S. stock of California sea lions is
not depleted under the MMPA. A regression of the natural logarithm of
the pup counts against year indicates that the counts of pups increased
at an annual rate of 5.4 percent between 1975 and 2008 (when pup counts
for El Ni[ntilde]o years were removed from the 1975-2005 time series).
These records of pup counts from 1975 to 2008 were compiled from Lowry
and Maravilla-Chavez (2005) and unpublished NMFS data. Consequently,
the activities are not expected to adversely impact annual rates of
recruitment or survival of California sea lion.
Preliminary Determination
Overall, the conclusions and predicted exposures in this analysis
find that overall impacts on marine mammal species and stocks would be
negligible for the following reasons:
All estimated acoustic harassments for the proposed
Civilian Port Defense training activities are within the non-injurious
temporary threshold shift (TTS) or behavioral effects zones (Level B
harassment), and these harassments (take numbers) represent only a
small percentage (less than 15 percent of bottlenose dolphin coastal
stock; less than 0.5 percent for all other species) of the respective
stock abundance for each species taken.
Marine mammal densities inputted into the model are also
overly conservative, particularly when considering species where data
is limited in portions of the proposed study area and seasonal
migrations extend throughout the Study Area.
The protective measures described in Proposed Mitigation
are designed to reduce sound exposure on marine mammals to levels below
those that may cause physiological effects (injury).
Animals exposed to acoustics from this two week event are
habituated to a bustling industrial port environment.
This proposed IHA assumes that short-term non-injurious SELs
predicted to cause onset-TTS or predicted SPLs predicted to cause
temporary behavioral disruptions (non-TTS) qualify as Level B
harassment. This approach predominately overestimates disturbances from
acoustic transmissions as qualifying as harassment under MMPA's
definition for military readiness activities because there is no
established scientific correlation between short term sonar use and
long term abandonment or significant alteration of behavioral patterns
in marine mammals.
Consideration of negligible impact is required for NMFS to
authorize incidental take of marine mammals. By definition, an activity
has a ``negligible impact'' on a species or stock when it is determined
that the total taking is not likely to reduce annual rates of adult
survival or recruitment (i.e., offspring survival, birth rates).
Behavioral reactions of marine mammals to sound are known to occur
but are difficult to predict. Recent behavioral studies indicate that
reactions to sounds, if any, are highly contextual and vary between
species and individuals within a species (Moretti et al., 2010;
Southall et al., 2011; Thompson et al., 2010; Tyack, 2009; Tyack et
al., 2011). Depending on the context, marine mammals often change their
activity when exposed to disruptive levels of sound. When sound becomes
potentially disruptive, cetaceans at rest become active, feeding or
socializing cetaceans or pinnipeds often interrupt these events by
diving or swimming away. If the sound disturbance occurs around a haul
out site, pinnipeds may move back and forth between water and land or
eventually abandon the haul out. When attempting to understand
behavioral disruption by anthropogenic sound, a key question to ask is
whether the exposures have biologically significant consequences for
the individual or population (National Research Council of the National
Academies, 2005).
If a marine mammal does react to an underwater sound by changing
its behavior or moving a small distance, the impacts of the change may
not be detrimental to the individual. For example, researchers have
found during a study focusing on dolphins response to whale watching
vessels in New Zealand, that when animals can cope with constraint and
easily feed or move elsewhere, there's little effect on survival
(Lusseau and Bejder, 2007). On the other hand, if a sound source
displaces marine mammals from an important feeding or breeding area for
a prolonged period and they do not have an alternate equally desirable
area, impacts on the marine mammal could be negative because the
disruption has biological consequences. Biological parameters or key
elements having greatest importance to a marine mammal relate to its
ability to mature, reproduce, and survive. For example, some elements
that should be considered include the following:
Growth: Adverse effects on ability to feed;
Reproduction: The range at which reproductive displays can
be heard and the quality of mating/calving grounds; and
Survival: Sound exposure may directly affect survival, for
example where sources of a certain type are deployed in a a manner that
could lead to a stranding response.
The importance of the disruption and degree of consequence for
individual marine mammals often has much to do with the frequency,
intensity, and duration of the disturbance. Isolated acoustic
disturbances such as acoustic transmissions usually have minimal
consequences or no lasting effects for marine mammals. Marine mammals
regularly cope with occasional disruption of their activities by
predators, adverse weather, and other natural phenomena. It is also
reasonable to assume that they can tolerate occasional or brief
disturbances by anthropogenic sound without significant consequences.
The exposure estimates calculated by predictive models currently
available reliably predict propagation of sound and received levels and
measure a short-term, immediate response of an individual using
applicable criteria. Consequences to populations are much more
difficult to predict and empirical measurement of population effects
from anthropogenic stressors is limited (National Research Council of
the National Academies, 2005). To predict indirect, long-term, and
cumulative effects, the processes must be well understood and the
underlying data available for models. Based on each species' life
history information, expected behavioral patterns in the Study Area,
all of the modeled exposures resulting in temporary behavioral
disturbance (Table 5), and the application of mitigation procedures
proposed above, the proposed Civilian Port Defense activities are
anticipated to have a negligible impact on marine mammal stocks within
the Study Area.
NMFS concludes that Civilian Port Defense training activities
within the Study Area would result in Level B takes only, as summarized
in Table 5.
[[Page 53688]]
The effects of these military readiness activities will be limited to
short-term, localized changes in behavior and possible temporary
threshold shift in the hearing of marine mammal species. These effects
are not likely to have a significant or long-term impact on feeding,
breeding, or other important biological functions. No take by injury or
mortality is anticipated, and the potential for permanent hearing
impairment is unlikely. Based on best available science NMFS concludes
that exposures to marine mammal species and stocks due to the proposed
training activities would result in only short-term effects from those
Level B takes to most individuals exposed and would likely not affect
annual rates of recruitment or survival.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat and dependent
upon the implementation of the mitigation and monitoring measures, NMFS
preliminarily finds that the total taking from Civilian Port Defense
training activities in the Study Area will have a negligible impact on
the affected species or stocks.
Subsistence Harvest of Marine Mammals
There are no relevant subsistence uses of marine mammals implicated
by this action. Therefore, NMFS has determined that the total taking of
affected species or stocks would not have an unmitigable adverse impact
on the availability of such species or stocks for taking for
subsistence purposes.
NEPA
The Navy is preparing an EA in accordance with the National
Environmental Policy Act (NEPA), to evaluate all components of the
proposed Civilian Port Defense training activities. NMFS intends to
adopt the Navy's EA, if adequate and appropriate. Currently, we believe
that the adoption of the Navy's EA will allow NMFS to meet its
responsibilities under NEPA for the issuance of an IHA to the Navy for
Civilian Port Defense activities at the Ports of Los Angeles and Long
Beach Harbor. If necessary, however, NMFS will supplement the existing
analysis to ensure that we comply with NEPA prior to the issuance of
the final IHA.
ESA
No species listed under the Endangered Species Act (ESA) are
expected to be affected by the proposed Civilian Port Defense training
activities and no takes of any ESA-listed species are requested or
proposed for authorization under the MMPA. Therefore, NMFS has
determined that a formal section 7 consultation under the ESA is not
required.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to the Navy for conducting Civilian Port Defense
activities from October to November 2015 on the U.S. west coast near
Los Angeles/Long Beach, California, provided the previously mentioned
mitigation, monitoring, and reporting requirements are incorporated.
The proposed IHA language is provided next.
This section contains a draft of the IHA itself. The wording
contained in this section is proposed for inclusion in the IHA (if
issued).
The Commander, U.S. Pacific Fleet, 250 Makalapa Drive, Pearl
Harbor, Hawaii 96860, and persons operating under his authority (i.e.,
Navy), is hereby authorized under section 101(a)(5)(D) of the Marine
Mammal Protection Act (16 U.S.C. 1371(a)(5)(D)) and 50 CFR 216.107, to
harass marine mammals incidental to Civilian Port Defense training
activities proposed to be conducted near the Ports of Los Angeles and
Long Beach from October to November 2015.
1. This Authorization is valid from October 25, 2015 through
November 25, 2015.
2. This Authorization is valid for the incidental taking of a
specified number of marine mammals, incidental to Civilian Port Defense
training activities proposed to be conducted near the Ports of Los
Angeles and Long Beach from October to November 2015, as described in
the Incidental Harassment Authorization (IHA) application.
3. The holder of this authorization (Holder) is hereby authorized
to take, by Level B harassment only, 8 long-beaked common dolphins
(Delphinus capensis), 727 short-beaked common dolphins (Delphinus
delphis), 21 Risso's dolphins (Grampus griseus), 40 Pacific white-sided
dolphins (Lagenorhynchus obilquidens), 48 bottlenose dolphins (Tursiops
truncates), 8 harbor seals (Phoca vitulina), and 46 California sea
lions (Zalophus californianus) incidental to Civilian Port Defense
training activities proposed to be conducted near the Ports of Los
Angeles and Long Beach, California.
4. The taking of any marine mammal in a manner prohibited under
this IHA must be reported immediately to NMFS' Office of Protected
Resources, 1315 East-West Highway, Silver Spring, MD 20910; phone 301-
427-8401; fax 301-713-0376.
5. Mitigation Requirements
The Holder is required to abide by the following mitigation
conditions listed in 5(a)-(b). Failure to comply with these conditions
may result in the modification, suspension, or revocation of this IHA.
(a) Lookouts
The following are protective measures concerning the use of
Lookouts:
Procedural Measures--The Navy will have two types of lookouts for
the purposes of conducting visual observations: (1) Those positioned on
surface ships, and (2) those positioned in aircraft or on boats.
Lookouts positioned on surface ships will be dedicated solely to
diligent observation of the air and surface of the water. Their
observation objectives will include, but are not limited to, detecting
the presence of biological resources and recreational or fishing boats,
observing mitigation zones, and monitoring for vessel and personnel
safety concerns. Lookouts positioned in aircraft or on boats will, to
the maximum extent practicable and consistent with aircraft and boat
safety and training requirements, comply with the observation
objectives described above for Lookouts positioned on surface ships.
Active Sonar--The Navy will have one Lookout on ships or aircraft
conducting high-frequency active sonar activities associated with mine
warfare activities at sea.
Vessels--While underway, vessels will have a minimum of one
Lookout.
Towed In-Water Devices--The Navy will have one Lookout during
activities using towed in-water devices when towed from a manned
platform.
(b) Mitigation Zones--The following are protective measures
concerning the implementation of mitigation zones:
Active Sonar--Mitigation will include visual observation from a
vessel or aircraft (with the exception of platforms operating at high
altitudes) immediately before and during active transmission within a
mitigation zone of 200 yards (yds. [183 m]) from the active sonar
source. If the source can be turned off during the activity, active
transmission will cease if a marine mammal is sighted within the
mitigation zone. Active transmission will recommence if any one of the
following conditions is met: (1) the animal is observed exiting the
mitigation zone, (2) the animal is thought to have exited the
mitigation zone based on a determination of its course and speed and
the relative motion between the animal and the source, (3) the
mitigation zone has been clear from any additional sightings for a
[[Page 53689]]
period of 10 minutes for an aircraft-deployed source, (4) the
mitigation zone has been clear from any additional sightings for a
period of 30 minutes for a vessel-deployed source, (5) the vessel or
aircraft has repositioned itself more than 400 yds (366 m) away from
the location of the last sighting, or (6) the vessel concludes that
dolphins are deliberately closing in to ride the vessel's bow wave (and
there are no other marine mammal sightings within the mitigation zone).
Vessels--Vessels will avoid approaching marine mammals head on and
will maneuver to maintain a mitigation zone of 500 yds (457 m) around
observed whales, and 200 yds (183 m) around all other marine mammals
(except bow riding dolphins), providing it is safe to do so.
Towed In-Water Devices--The Navy will ensure that towed in-water
devices being towed from manned platforms avoid coming within a
mitigation zone of 250 yds (229 m) around any observed marine mammal,
providing it is safe to do so.
6. Monitoring and Reporting Requirements
The Holder is required to abide by the following monitoring and
reporting conditions. Failure to comply with these conditions may
result in the modification, suspension, or revocation of this IHA.
General Notification of Injured or Dead Marine Mammals--If any
injury or death of a marine mammal is observed during the Civilian Port
Defense training activity, the Navy will immediately halt the activity
and report the incident to NMFS following the standard monitoring and
reporting measures consistent with the MITT EIS/OEIS. The reporting
measures include the following procedures:
Navy personnel shall ensure that NMFS (regional stranding
coordinator) is notified immediately (or as soon as clearance
procedures allow) if an injured or dead marine mammal is found during
or shortly after, and in the vicinity of, any Navy training activity
utilizing high-frequency active sonar. The Navy shall provide NMFS with
species or description of the animal(s), the condition of the animal(s)
(including carcass condition if the animal is dead), location, time of
first discovery, observed behaviors (if alive), and photo or video (if
available). The Navy shall consult the Stranding Response and
Communication Plan to obtain more specific reporting requirements for
specific circumstances.
Vessel Strike--Vessel strike during Navy Civilian Port Defense
activities in the Study Area is not anticipated; however, in the event
that a Navy vessel strikes a whale, the Navy shall do the following:
Immediately report to NMFS (pursuant to the established
Communication Protocol) the:
Species identification (if known);
Location (latitude/longitude) of the animal (or location
of the strike if the animal has disappeared);
Whether the animal is alive or dead (or unknown); and
The time of the strike.
As soon as feasible, the Navy shall report to or provide to NMFS,
the:
Size, length, and description (critical if species is not
known) of animal;
An estimate of the injury status (e.g., dead, injured but
alive, injured and moving, blood or tissue observed in the water,
status unknown, disappeared, etc.);
Description of the behavior of the whale during event,
immediately after the strike, and following the strike (until the
report is made or the animal is no longer sighted);
Vessel class/type and operational status;
Vessel length;
Vessel speed and heading; and
To the best extent possible, obtain a photo or video of
the struck animal, if the animal is still in view.
Within 2 weeks of the strike, provide NMFS:
A detailed description of the specific actions of the
vessel in the 30-minute timeframe immediately preceding the strike,
during the event, and immediately after the strike (e.g., the speed and
changes in speed, the direction and changes in direction, other
maneuvers, sonar use, etc., if not classified);
A narrative description of marine mammal sightings during
the event and immediately after, and any information as to sightings
prior to the strike, if available; and use established Navy shipboard
procedures to make a camera available to attempt to capture photographs
following a ship strike.
NMFS and the Navy will coordinate to determine the services the
Navy may provide to assist NMFS with the investigation of the strike.
The response and support activities to be provided by the Navy are
dependent on resource availability, must be consistent with military
security, and must be logistically feasible without compromising Navy
personnel safety. Assistance requested and provided may vary based on
distance of strike from shore, the nature of the vessel that hit the
whale, available nearby Navy resources, operational and installation
commitments, or other factors.
7. A copy of this Authorization must be in the possession of the
on-site Commanding Officer in order to take marine mammals under the
authority of this Incidental Harassment Authorization while conducting
the specified activities.
8. This Authorization may be modified, suspended, or withdrawn if
the Holder or any person operating under his authority fails to abide
by the conditions prescribed herein or if the authorized taking is
having more than a negligible impact on the species or stock of
affected marine mammals.
Request for Public Comments
NMFS requests comment on our analysis, the draft authorization, and
any other aspect of the Notice of Proposed IHA for the Navy's Civilian
Port Defense training activities. Please include with your comments any
supporting data or literature citations to help inform our final
decision on the Navy's request for an MMPA authorization.
Dated: August 31, 2015.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2015-21911 Filed 9-3-15; 8:45 am]
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